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Commit Graph

13809 Commits

Author SHA1 Message Date
Paul E. McKenney
62fde6edf1 rcu: Make __call_rcu() handle invocation from idle
Although __call_rcu() is handled correctly when called from a momentary
non-idle period, if it is called on a CPU that RCU believes to be idle
on RCU_FAST_NO_HZ kernels, the callback might be indefinitely postponed.
This commit therefore ensures that RCU is aware of the new callback and
has a chance to force the CPU out of dyntick-idle mode when a new callback
is posted.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:24 -07:00
Paul E. McKenney
2a3fa843b5 rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations
The CONFIG_TREE_PREEMPT_RCU and CONFIG_TINY_PREEMPT_RCU versions of
__rcu_read_lock() and __rcu_read_unlock() are identical, so this commit
consolidates them into kernel/rcupdate.h.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:23 -07:00
Paul E. McKenney
1d1fb395f6 rcu: Add ACCESS_ONCE() to ->qlen accesses
The _rcu_barrier() function accesses other CPUs' rcu_data structure's
->qlen field without benefit of locking.  This commit therefore adds
the required ACCESS_ONCE() wrappers around accesses and updates that
need it.

ACCESS_ONCE() is not needed when a CPU accesses its own ->qlen, or
in code that cannot run while _rcu_barrier() is sampling ->qlen fields.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:22 -07:00
Paul E. McKenney
3f5d3ea64f rcu: Consolidate duplicate callback-list initialization
There are a couple of open-coded initializations of the rcu_data
structure's RCU callback list.  This commit therefore consolidates
them into a new init_callback_list() function.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:21 -07:00
Paul E. McKenney
285fe29481 rcu: Fix detection of abruptly-ending stall
The code that attempts to identify stalls that end just as we detect
them is broken by both flavors of initialization failure.  This commit
therefore properly initializes and computes the count of the number
of reasons why the RCU grace period is stalled.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:21 -07:00
Paul E. McKenney
72472a02a9 rcu: Make rcutorture fakewriters invoke rcu_barrier()
The current rcutorture rcu_barrier() testing never intentionally runs
more than one instance of rcu_barrier() at a given time.  This fails
to test the the shiny new concurrency features of rcu_barrier().  This
commit therefore modifies the rcutorture fakewriter kthread to randomly
invoke rcu_barrier() rather than the usual synchronize_rcu().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:34:04 -07:00
Paul E. McKenney
143aa672f4 rcu: Fix diagnostic-printk typo in rcutorture
The rcu_torture_barrier() function has a copy-and-paste typo in the
string passed to rcutorture_shutdown_absorb(), which this commit fixes.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:03 -07:00
Paul E. McKenney
c6ebcbb60c rcu: Fix bug in rcu_barrier() torture test
The child threads in the rcu_torture_barrier_cbs() are improperly
synchronized, which can cause the rcu_barrier() tests to hang.  The
failure mode is as follows:

1.	CPU 0 running in rcu_torture_barrier() sets barrier_cbs_count
    	to n_barrier_cbs.

2.	CPU 1 running in rcu_torture_barrier_cbs() wakes up, posts
    	its RCU callback, and atomically decrements barrier_cbs_count.
    	Because barrier_cbs_count is not zero, it does not do the wake_up().

3.	CPU 2 running in rcu_torture_barrier_cbs() wakes up, but
    	finds that barrier_cbs_count is not equal to n_barrier_cbs,
    	and so returns to sleep.

4.	The value of barrier_cbs_count therefore never reaches zero,
    	which causes the test to hang.

This commit therefore uses a phase variable to coordinate the test,
preventing this scenario from occurring.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:34:03 -07:00
Paul E. McKenney
e3f8d3788e rcu: Test srcu_barrier() from rcutorture test suite
SRCU now has a call_srcu() and an srcu_barrier(), but rcutorture does not
test them.  This commit adds the machinery to allow rcutorture's existing
tests for call_rcu() and rcu_barrier() to apply to the SRCU equivalents.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:03 -07:00
Paul E. McKenney
751a68b2e4 rcu: Rationalize ordering of torture_ops list
Move the raw SRCU interfaces out of the middle of the normal SRCU
interfaces.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:34:03 -07:00
Paul E. McKenney
ff015030c9 rcu: RCU_SAVE_DYNTICK code no longer ever dead
Before RCU had unified idle, the RCU_SAVE_DYNTICK leg of the switch
statement in force_quiescent_state() was dead code for CONFIG_NO_HZ=n
kernel builds.  With unified idle, the code is never dead.  This commit
therefore removes the "if" statement designed to make gcc aware of when
the code was and was not dead.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:24 -07:00
Paul E. McKenney
c0cc962da3 rcu: Use for_each_rcu_flavor() in TREE_RCU tracing
This commit applies the new for_each_rcu_flavor() macro to the
kernel/rcutree_trace.c file.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:24 -07:00
Paul E. McKenney
6ce75a2326 rcu: Introduce for_each_rcu_flavor() and use it
The arrival of TREE_PREEMPT_RCU some years back included some ugly
code involving either #ifdef or #ifdef'ed wrapper functions to iterate
over all non-SRCU flavors of RCU.  This commit therefore introduces
a for_each_rcu_flavor() iterator over the rcu_state structures for each
flavor of RCU to clean up a bit of the ugliness.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:24 -07:00
Paul E. McKenney
1bca8cf1a2 rcu: Remove unneeded __rcu_process_callbacks() argument
With the advent of __this_cpu_ptr(), it is no longer necessary to pass
both the rcu_state and rcu_data structures into __rcu_process_callbacks().
This commit therefore computes the rcu_data pointer from the rcu_state
pointer within __rcu_process_callbacks() so that callers can pass in
only the pointer to the rcu_state structure.  This paves the way for
linking the rcu_state structures together and iterating over them.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:23 -07:00
Paul E. McKenney
d7e187c8e9 rcu: Add rcu_barrier() statistics to debugfs tracing
This commit adds an rcubarrier file to RCU's debugfs statistical tracing
directory, providing diagnostic information on rcu_barrier().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:23 -07:00
Paul E. McKenney
a83eff0a82 rcu: Add tracing for _rcu_barrier()
This commit adds event tracing for _rcu_barrier() execution.  This
is defined only if RCU_TRACE=y.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:23 -07:00
Paul E. McKenney
cf3a9c4842 rcu: Increase rcu_barrier() concurrency
The traditional rcu_barrier() implementation has serialized all requests,
regardless of RCU flavor, and also does not coalesce concurrent requests.
In the past, this has been good and sufficient.

However, systems are getting larger and use of rcu_barrier() has been
increasing.  This commit therefore introduces a counter-based scheme
that allows _rcu_barrier() calls for the same flavor of RCU to take
advantage of each others' work.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:23 -07:00
Paul E. McKenney
cfed0a85da rcu: Remove needless initialization
For global variables, C defaults all fields to zero.  The initialization
of the rcu_state structure's ->n_force_qs and ->n_force_qs_ngp fields
is therefore redundant, so this commit removes these initializations.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:22 -07:00
Paul E. McKenney
7be7f0be90 rcu: Move rcu_barrier_mutex to rcu_state structure
In order to allow each RCU flavor to concurrently execute its
rcu_barrier() function, it is necessary to move the relevant
state to the rcu_state structure.  This commit therefore moves the
rcu_barrier_mutex global variable to a new ->barrier_mutex field
in the rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:22 -07:00
Paul E. McKenney
7db74df88b rcu: Move rcu_barrier_completion to rcu_state structure
In order to allow each RCU flavor to concurrently execute its
rcu_barrier() function, it is necessary to move the relevant
state to the rcu_state structure.  This commit therefore moves the
rcu_barrier_completion global variable to a new ->barrier_completion
field in the rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:22 -07:00
Paul E. McKenney
24ebbca8ec rcu: Move rcu_barrier_cpu_count to rcu_state structure
In order to allow each RCU flavor to concurrently execute its rcu_barrier()
function, it is necessary to move the relevant state to the rcu_state
structure.  This commit therefore moves the rcu_barrier_cpu_count global
variable to a new ->barrier_cpu_count field in the rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:22 -07:00
Paul E. McKenney
06668efa91 rcu: Move _rcu_barrier()'s rcu_head structures to rcu_data structures
In order for multiple flavors of RCU to each concurrently run one
rcu_barrier(), each flavor needs its own per-CPU set of rcu_head
structures.  This commit therefore moves _rcu_barrier()'s set of
per-CPU rcu_head structures from per-CPU variables to the existing
per-CPU and per-RCU-flavor rcu_data structures.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:21 -07:00
Paul E. McKenney
037b64ed0b rcu: Place pointer to call_rcu() in rcu_data structure
This is a preparatory commit for increasing rcu_barrier()'s concurrency.
It adds a pointer in the rcu_data structure to the corresponding call_rcu()
function.  This allows a pointer to the rcu_data structure to imply the
function pointer, which allows _rcu_barrier() state to be placed in the
rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:21 -07:00
Paul E. McKenney
6c90cc7bf0 rcu: Prevent excessive line length in RCU_STATE_INITIALIZER()
Upcoming rcu_barrier() concurrency commits will result in line lengths
greater than 80 characters in the RCU_STATE_INITIALIZER(), so this commit
shortens the name of the macro's argument to prevent this.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-07-02 12:33:21 -07:00
Paul E. McKenney
cca6f39319 rcu: Size rcu_node tree from nr_cpu_ids rather than NR_CPUS
The rcu_node tree array is sized based on compile-time constants,
including NR_CPUS.  Although this approach has worked well in the past,
the recent trend by many distros to define NR_CPUS=4096 results in
excessive grace-period-initialization latencies.

This commit therefore substitutes the run-time computed nr_cpu_ids for
the compile-time NR_CPUS when building the tree.  This can result in
much of the compile-time-allocated rcu_node array being unused.  If
this is a major problem, you are in a specialized situation anyway,
so you can manually adjust the NR_CPUS, RCU_FANOUT, and RCU_FANOUT_LEAF
kernel config parameters.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:21 -07:00
Paul E. McKenney
cc5df65b03 rcu: Four-level hierarchy is no longer experimental
Time to make the four-level-hierarchy setting less scary, so this
commit removes "Experimental" from the boot-time message.  Leave the
message in order to get a heads-up on any possible need to expand to
a five-level hierarchy.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:20 -07:00
Paul E. McKenney
f885b7f2b2 rcu: Control RCU_FANOUT_LEAF from boot-time parameter
Although making RCU_FANOUT_LEAF a kernel configuration parameter rather
than a fixed constant makes it easier for people to decrease cache-miss
overhead for large systems, it is of little help for people who must
run a single pre-built kernel binary.

This commit therefore allows the value of RCU_FANOUT_LEAF to be
increased (but not decreased!) via a boot-time parameter named
rcutree.rcu_fanout_leaf.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2012-07-02 12:33:20 -07:00
Paul E. McKenney
cba6d0d64e Revert "rcu: Move PREEMPT_RCU preemption to switch_to() invocation"
This reverts commit 616c310e83.
(Move PREEMPT_RCU preemption to switch_to() invocation).
Testing by Sasha Levin <levinsasha928@gmail.com> showed that this
can result in deadlock due to invoking the scheduler when one of
the runqueue locks is held.  Because this commit was simply a
performance optimization, revert it.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
2012-07-02 11:39:19 -07:00
Bojan Smojver
d8150d3504 PM / Hibernate: Print hibernation/thaw progress indicator one line at a time.
With the introduction of suspend to both into in-kernel hibernation
code, dmesg was getting polluted with backspace characters printed as
part of image saving progress indicator. This patch introduces printing
of progress indicator on image save/load every 10% and one line at a
time. As an additional benefit, all other messages emitted by the kernel
during hibernation/thaw should now print cleanly as well.

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:31:23 +02:00
Rafael J. Wysocki
b2df1d4f8b PM / Sleep: Separate printing suspend times from initcall_debug
Change the behavior of the newly introduced
/sys/power/pm_print_times attribute so that its initial value
depends on initcall_debug, but setting it to 0 will cause device
suspend/resume times not to be printed, even if initcall_debug has
been set.  This way, the people who use initcall_debug for reasons
other than PM debugging will be able to switch the suspend/resume
times printing off, if need be.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-01 13:31:23 +02:00
Sameer Nanda
4b7760ba0d PM / Sleep: add knob for printing device resume times
Added a new knob called /sys/power/pm_print_times. Setting it to 1
enables printing of time taken by devices to suspend and resume.
Setting it to 0 disables this printing (unless overridden by
initcall_debug kernel command line option).

Signed-off-by: Sameer Nanda <snanda@chromium.org>
Acked-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:31:22 +02:00
Srivatsa S. Bhat
443772d408 ftrace: Disable function tracing during suspend/resume and hibernation, again
If function tracing is enabled for some of the low-level suspend/resume
functions, it leads to triple fault during resume from suspend, ultimately
ending up in a reboot instead of a resume (or a total refusal to come out
of suspended state, on some machines).

This issue was explained in more detail in commit f42ac38c59 (ftrace:
disable tracing for suspend to ram). However, the changes made by that commit
got reverted by commit cbe2f5a6e8 (tracing: allow tracing of
suspend/resume & hibernation code again). So, unfortunately since things are
not yet robust enough to allow tracing of low-level suspend/resume functions,
suspend/resume is still broken when ftrace is enabled.

So fix this by disabling function tracing during suspend/resume & hibernation.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:31:22 +02:00
Bojan Smojver
62c552ccc3 PM / Hibernate: Enable suspend to both for in-kernel hibernation.
It is often useful to suspend to memory after hibernation image has been
written to disk. If the battery runs out or power is otherwise lost, the
computer will resume from the hibernated image. If not, it will resume
from memory and hibernation image will be discarded.

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-07-01 13:31:22 +02:00
Randy Dunlap
4f0f4af59c printk.c: fix kernel-doc warnings
Fix kernel-doc warnings in printk.c: use correct parameter name.

  Warning(kernel/printk.c:2429): No description found for parameter 'buf'
  Warning(kernel/printk.c:2429): Excess function parameter 'line' description in 'kmsg_dump_get_buffer'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-30 15:56:40 -07:00
Linus Torvalds
21f27291f5 Driver Core fixes for 3.5-rc5
Here is a number of printk() fixes, specifically a few reported by the
 crazy blog program that ships in SUSE releases (that's "boot log" and
 not "web log", it predates the general "blog" terminology by many
 years), and the restoration of the continuation line functionality
 reported by Stephen and others.  Yes, the changes seem a bit big this
 late in the cycle, but I've been beating on them for a while now, and
 Stephen has even optimized it a bit, so all looks good to me.
 
 The other change in here is a Documentation update for the stable kernel
 rules describing how some distro patches should be backported, to
 hopefully drive a bit more response from the distros to the stable
 kernel releases.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver Core fixes from Greg Kroah-Hartman:
 "Here is a number of printk() fixes, specifically a few reported by the
  crazy blog program that ships in SUSE releases (that's "boot log" and
  not "web log", it predates the general "blog" terminology by many
  years), and the restoration of the continuation line functionality
  reported by Stephen and others.  Yes, the changes seem a bit big this
  late in the cycle, but I've been beating on them for a while now, and
  Stephen has even optimized it a bit, so all looks good to me.

  The other change in here is a Documentation update for the stable
  kernel rules describing how some distro patches should be backported,
  to hopefully drive a bit more response from the distros to the stable
  kernel releases.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'driver-core-3.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  printk: Optimize if statement logic where newline exists
  printk: flush continuation lines immediately to console
  syslog: fill buffer with more than a single message for SYSLOG_ACTION_READ
  Revert "printk: return -EINVAL if the message len is bigger than the buf size"
  printk: fix regression in SYSLOG_ACTION_CLEAR
  stable: Allow merging of backports for serious user-visible performance issues
2012-06-30 10:11:24 -07:00
Pablo Neira Ayuso
a31f2d17b3 netlink: add netlink_kernel_cfg parameter to netlink_kernel_create
This patch adds the following structure:

struct netlink_kernel_cfg {
        unsigned int    groups;
        void            (*input)(struct sk_buff *skb);
        struct mutex    *cb_mutex;
};

That can be passed to netlink_kernel_create to set optional configurations
for netlink kernel sockets.

I've populated this structure by looking for NULL and zero parameters at the
existing code. The remaining parameters that always need to be set are still
left in the original interface.

That includes optional parameters for the netlink socket creation. This allows
easy extensibility of this interface in the future.

This patch also adapts all callers to use this new interface.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-29 16:46:02 -07:00
Steven Rostedt
d36208227d printk: Optimize if statement logic where newline exists
In reviewing Kay's fix up patch: "printk: Have printk() never buffer its
data", I found two if statements that could be combined and optimized.

Put together the two 'cont.len && cont.owner == current' if statements
into a single one, and check if we need to call cont_add(). This also
removes the unneeded double cont_flush() calls.

Link: http://lkml.kernel.org/r/1340869133.876.10.camel@mop

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-29 16:55:35 -04:00
Vaibhav Nagarnaik
48fdc72f23 ring-buffer: Fix accounting of entries when removing pages
When removing pages from the ring buffer, its state is not reset. This
means that the counters need to be correctly updated to account for the
pages removed.

Update the overrun counter to reflect the removed events from the pages.

Link: http://lkml.kernel.org/r/1340998301-1715-1-git-send-email-vnagarnaik@google.com

Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-29 16:17:17 -04:00
Vaibhav Nagarnaik
44b99462d9 ring-buffer: Fix crash due to uninitialized new_pages list head
The new_pages list head in the cpu_buffer is not initialized. When
adding pages to the ring buffer, if the memory allocation fails in
ring_buffer_resize, the clean up handler tries to free up the allocated
pages from all the cpu buffers. The panic is caused by referencing the
uninitialized new_pages list head.

Initializing the new_pages list head in rb_allocate_cpu_buffer fixes
this.

Link: http://lkml.kernel.org/r/1340391005-10880-1-git-send-email-vnagarnaik@google.com

Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-29 16:16:35 -04:00
Kay Sievers
084681d14e printk: flush continuation lines immediately to console
Continuation lines are buffered internally, intended to merge the
chunked printk()s into a single record, and to isolate potentially
racy continuation users from usual terminated line users.

This though, has the effect that partial lines are not printed to
the console in the moment they are emitted. In case the kernel
crashes in the meantime, the potentially interesting printed
information would never reach the consoles.

Here we share the continuation buffer with the console copy logic,
and partial lines are always immediately flushed to the available
consoles. They are still buffered internally to improve the
readability and integrity of the messages and minimize the amount
of needed record headers to store.

Signed-off-by: Kay Sievers <kay@vrfy.org>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-29 11:39:42 -04:00
David S. Miller
b26d344c6b Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/caif/caif_hsi.c
	drivers/net/usb/qmi_wwan.c

The qmi_wwan merge was trivial.

The caif_hsi.c, on the other hand, was not.  It's a conflict between
1c385f1fdf ("caif-hsi: Replace platform
device with ops structure.") in the net-next tree and commit
39abbaef19 ("caif-hsi: Postpone init of
HIS until open()") in the net tree.

I did my best with that one and will ask Sjur to check it out.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-28 17:37:00 -07:00
Steven Rostedt
a5fb833172 ring-buffer: Fix uninitialized read_stamp
The ring buffer reader page is used to swap a page from the writable
ring buffer. If the writer happens to be on that page, it ends up on the
reader page, but will simply move off of it, back into the writable ring
buffer as writes are added.

The time stamp passed back to the readers is stored in the cpu_buffer per
CPU descriptor. This stamp is updated when a swap of the reader page takes
place, and it reads the current stamp from the page taken from the writable
ring buffer. Everytime a writer goes to a new page, it updates the time stamp
of that page.

The problem happens if a reader reads a page from an empty per CPU ring buffer.
If the buffer is empty, the swap still takes place, placing the writer at the
start of the reader page. If at a later time, a write happens, it updates the
page's time stamp and continues. But the problem is that the read_stamp does
not get updated, because the page was already swapped.

The solution to this was to not swap the page if the ring buffer happens to
be empty. This also removes the side effect that the writes on the reader
page will not get updated because the writer never gets back on the reader
page without a swap. That is, if a read happens on an empty buffer, but then
no reads happen for a while. If a swap took place, and the writer were to start
writing a lot of data (function tracer), it will start overflowing the ring buffer
and overwrite the older data. But because the writer never goes back onto the
reader page, the data left on the reader page never gets overwritten. This
causes the reader to see really old data, followed by a jump to newer data.

Link: http://lkml.kernel.org/r/1340060577-9112-1-git-send-email-dhsharp@google.com
Google-Bug-Id: 6410455
Reported-by: David Sharp <dhsharp@google.com>
tested-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-28 13:52:15 -04:00
Steven Rostedt
6d158a813e tracing: Remove NR_CPUS array from trace_iterator
Replace the NR_CPUS array of buffer_iter from the trace_iterator
with an allocated array. This will just create an array of
possible CPUS instead of the max number specified.

The use of NR_CPUS in that array caused allocation failures for
machines that were tight on memory. This did not cause any failures
to the system itself (no crashes), but caused unnecessary failures
for reading the trace files.

Added a helper function called 'trace_buffer_iter()' that returns
the buffer_iter item or NULL if it is not defined or the array was
not allocated. Some routines do not require the array
(tracing_open_pipe() for one).

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-28 13:52:15 -04:00
Steven Rostedt
0be61ebc18 tracing/selftest: Add a WARN_ON() if a tracer test fails
Add a WARN_ON() output on test failures so that they are easier to detect
in automated tests. Although, the WARN_ON() will not print if the test
causes the system to crash, obviously.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-28 13:52:14 -04:00
David S. Miller
c64e66c67b audit: netlink: Move away from NLMSG_NEW().
And use nlmsg_data() while we're here too.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-26 21:54:14 -07:00
Jan Beulich
116e90b23f syslog: fill buffer with more than a single message for SYSLOG_ACTION_READ
The recent changes to the printk buffer management resulted in
SYSLOG_ACTION_READ to only return a single message, whereas previously
the buffer would get filled as much as possible. As, when too small to
fit everything, filling it to the last byte would be pretty ugly with
the new code, the patch arranges for as many messages as possible to
get returned in a single invocation. User space tools in at least all
SLES versions depend on the old behavior.

This at once addresses the issue attempted to get fixed with commit
b56a39ac26 ("printk: return -EINVAL if
the message len is bigger than the buf size"), and since that commit
widened the possibility for losing a message altogether, the patch
here assumes that this other commit would get reverted first
(otherwise the patch here won't apply).

Furthermore, this patch also addresses the problem dealt with in
commit 4a77a5a06e ("printk: use mutex
lock to stop syslog_seq from going wild"), so I'd recommend reverting
that one too (albeit there's no direct collision between the two).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kay Sievers <kay@vrfy.org>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-26 12:37:36 -07:00
Greg Kroah-Hartman
6fda135c90 Revert "printk: return -EINVAL if the message len is bigger than the buf size"
This reverts commit b56a39ac26.

A better patch from Jan will follow this to resolve the issue.

Acked-by: Kay Sievers <kay@vrfy.org>
Cc: Fengguang Wu <wfg@linux.intel.com>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-26 12:35:24 -07:00
Paul E. McKenney
b41772abeb rcu: Stop rcu_do_batch() from multiplexing the "count" variable
Commit b1420f1c (Make rcu_barrier() less disruptive) rearranged the
code in rcu_do_batch(), moving the ->qlen manipulation to follow
the requeueing of the callbacks.  Unfortunately, this rearrangement
clobbered the value of the "count" local variable before the value
of rdp->qlen was adjusted, resulting in the value of rdp->qlen being
inaccurate.  This commit therefore introduces an index variable "i",
avoiding the inadvertent multiplexing.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2012-06-25 12:35:25 -07:00
Alan Stern
4661e3568a printk: fix regression in SYSLOG_ACTION_CLEAR
Commit 7ff9554bb5 (printk: convert
byte-buffer to variable-length record buffer) introduced a regression
by accidentally removing a "break" statement from inside the big
switch in printk's do_syslog().  The symptom of this bug is that the
"dmesg -C" command doesn't only clear the kernel's log buffer; it also
disables console logging.

This patch (as1561) fixes the regression by adding the missing
"break".

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-25 12:11:58 -07:00
David S. Miller
dfbce08c19 ipv4: Don't add deprecated new binary sysctl value.
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-22 23:02:22 -07:00
Alexander Duyck
6648bd7e0e ipv4: Add sysctl knob to control early socket demux
This change is meant to add a control for disabling early socket demux.
The main motivation behind this patch is to provide an option to disable
the feature as it adds an additional cost to routing that reduces overall
throughput by up to 5%.  For example one of my systems went from 12.1Mpps
to 11.6 after the early socket demux was added.  It looks like the reason
for the regression is that we are now having to perform two lookups, first
the one for an established socket, and then the one for the routing table.

By adding this patch and toggling the value for ip_early_demux to 0 I am
able to get back to the 12.1Mpps I was previously seeing.

[ Move local variables in ip_rcv_finish() down into the basic
  block in which they are actually used.  -DaveM ]

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-22 17:11:13 -07:00
Linus Torvalds
a11637194a Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar.

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ftrace: Make all inline tags also include notrace
  perf: Use css_tryget() to avoid propping up css refcount
  perf tools: Fix synthesizing tracepoint names from the perf.data headers
  perf stat: Fix default output file
  perf tools: Fix endianity swapping for adds_features bitmask
2012-06-22 10:58:57 -07:00
Linus Torvalds
2ce5682947 Merge branch 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull two cgroup fixes from Tejun Heo:
 "This containes two patches fixing a refcnt race bug during css_put().
  Decrementing and checking the value weren't atomic and two tasks could
  think that they both pushed the counter to zero."

* 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroups: Account for CSS_DEACT_BIAS in __css_put
  cgroup: make sure that decisions in __css_put are atomic
2012-06-20 22:11:04 -07:00
Linus Torvalds
fe80352460 Driver core and printk fixes for 3.5-rc4
Here are some fixes for 3.5-rc4 that resolve the kmsg problems that
 people have reported showing up after the printk and kmsg changes went
 into 3.5-rc1.  There are also a smattering of other tiny fixes for the
 extcon and hyper-v drivers that people have reported.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core and printk fixes from Greg Kroah-Hartman:
 "Here are some fixes for 3.5-rc4 that resolve the kmsg problems that
  people have reported showing up after the printk and kmsg changes went
  into 3.5-rc1.  There are also a smattering of other tiny fixes for the
  extcon and hyper-v drivers that people have reported.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'driver-core-3.5-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  extcon: max8997: Add missing kfree for info->edev in max8997_muic_remove()
  extcon: Set platform drvdata in gpio_extcon_probe() and fix irq leak
  extcon: Fix wrong index in max8997_extcon_cable[]
  kmsg - kmsg_dump() fix CONFIG_PRINTK=n compilation
  printk: return -EINVAL if the message len is bigger than the buf size
  printk: use mutex lock to stop syslog_seq from going wild
  kmsg - kmsg_dump() use iterator to receive log buffer content
  vme: change maintainer e-mail address
  Extcon: Don't try to create duplicate link names
  driver core: fixup reversed deferred probe order
  printk: Fix alignment of buf causing crash on ARM EABI
  Tools: hv: verify origin of netlink connector message
2012-06-20 15:14:28 -07:00
Cyrill Gorcunov
5702c5eeab c/r: prctl: Move PR_GET_TID_ADDRESS to a proper place
During merging of PR_GET_TID_ADDRESS patch the code has been misplaced (it
happened to appear under PR_MCE_KILL) in result noone can use this option.

Fix it by moving code snippet to a proper place.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-20 14:39:36 -07:00
Oleg Nesterov
50d75f8dae pidns: find_new_reaper() can no longer switch to init_pid_ns.child_reaper
find_new_reaper() changes pid_ns->child_reaper, see add0d4df ("pid_ns:
zap_pid_ns_processes: fix the ->child_reaper changing").

The original reason has gone away after the previous patch, ->children
list must be empty after zap_pid_ns_processes().

However now we can not switch to init_pid_ns.child_reaper.
__unhash_process() relies on the "->child_reaper == parent" check, but
this check does not work if the last exiting task is also the child
reaper.

As Eric sugested, we can change __unhash_process() to use the parent's
pid_ns and remove this code.

Also, with this change we can move detach_pid(PIDTYPE_PID) back, where it
was before the previous fix.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Mike Galbraith <efault@gmx.de>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Tested-by: Andrew Wagin <avagin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-20 14:39:36 -07:00
Eric W. Biederman
6347e90091 pidns: guarantee that the pidns init will be the last pidns process reaped
Today we have a twofold bug.  Sometimes release_task on pid == 1 in a pid
namespace can run before other processes in a pid namespace have had
release task called.  With the result that pid_ns_release_proc can be
called before the last proc_flus_task() is done using upid->ns->proc_mnt,
resulting in the use of a stale pointer.  This same set of circumstances
can lead to waitpid(...) returning for a processes started with
clone(CLONE_NEWPID) before the every process in the pid namespace has
actually exited.

To fix this modify zap_pid_ns_processess wait until all other processes in
the pid namespace have exited, even EXIT_DEAD zombies.

The delay_group_leader and related tests ensure that the thread gruop
leader will be the last thread of a process group to be reaped, or to
become EXIT_DEAD and self reap.  With the change to zap_pid_ns_processes
we get the guarantee that pid == 1 in a pid namespace will be the last
task that release_task is called on.

With pid == 1 being the last task to pass through release_task
pid_ns_release_proc can no longer be called too early nor can wait return
before all of the EXIT_DEAD tasks in a pid namespace have exited.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Mike Galbraith <efault@gmx.de>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Tested-by: Andrew Wagin <avagin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-20 14:39:36 -07:00
Konstantin Khlebnikov
4fe7efdbdf mm: correctly synchronize rss-counters at exit/exec
do_exit() and exec_mmap() call sync_mm_rss() before mm_release() does
put_user(clear_child_tid) which can update task->rss_stat and thus make
mm->rss_stat inconsistent.  This triggers the "BUG:" printk in check_mm().

Let's fix this bug in the safest way, and optimize/cleanup this later.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-20 14:39:36 -07:00
Salman Qazi
8e3bbf42c6 cgroups: Account for CSS_DEACT_BIAS in __css_put
When we fixed the race between atomic_dec and css_refcnt, we missed
the fact that css_refcnt internally subtracts CSS_DEACT_BIAS to get
the actual reference count.  This can potentially cause a refcount leak
if __css_put races with cgroup_clear_css_refs.

Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2012-06-18 15:38:02 -07:00
Yan, Zheng
0cda4c0231 perf: Introduce perf_pmu_migrate_context()
Originally from Peter Zijlstra. The helper migrates perf events
from one cpu to another cpu.

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-5-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 12:13:21 +02:00
Yan, Zheng
e2d37cd213 perf: Allow the PMU driver to choose the CPU on which to install events
Allow the pmu->event_init callback to change event->cpu, so the PMU driver
can choose the CPU on which to install events.

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-4-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 12:13:21 +02:00
Yan, Zheng
fbfc623f82 perf: Avoid race between cpu hotplug and installing event
perf_event_open() requires the cpu on which to install event is online,
but the cpu can go offline after perf_event_open checks that. Add a
get_online_cpus()/put_online_cpus() pair to avoid the race.

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1339741902-8449-3-git-send-email-zheng.z.yan@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 12:13:20 +02:00
Ingo Molnar
d1ece0998e Merge branch 'perf/urgent' into perf/core
Merge in all fixes before applying more changes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 11:47:58 +02:00
Salman Qazi
9c5da09d26 perf: Use css_tryget() to avoid propping up css refcount
An rmdir pushes css's ref count to zero.  However, if the associated
directory is open at the time, the dentry ref count is non-zero.  If
the fd for this directory is then passed into perf_event_open, it
does a css_get().  This bounces the ref count back up from zero.  This
is a problem by itself.  But what makes it turn into a crash is the
fact that we end up doing an extra dput, since we perform a dput
when css_put sees the ref count go down to zero.

css_tryget() does not fall into that trap. So, we use that instead.

Reproduction test-case for the bug:

 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <linux/unistd.h>
 #include <linux/perf_event.h>
 #include <string.h>
 #include <errno.h>
 #include <stdio.h>

 #define PERF_FLAG_PID_CGROUP    (1U << 2)

 int perf_event_open(struct perf_event_attr *hw_event_uptr,
                     pid_t pid, int cpu, int group_fd, unsigned long flags) {
         return syscall(__NR_perf_event_open,hw_event_uptr, pid, cpu,
                 group_fd, flags);
 }

 /*
  * Directly poke at the perf_event bug, since it's proving hard to repro
  * depending on where in the kernel tree.  what moved?
  */
 int main(int argc, char **argv)
 {
        int fd;
        struct perf_event_attr attr;
        memset(&attr, 0, sizeof(attr));
        attr.exclude_kernel = 1;
        attr.size = sizeof(attr);
        mkdir("/dev/cgroup/perf_event/blah", 0777);
        fd = open("/dev/cgroup/perf_event/blah", O_RDONLY);
        perror("open");
        rmdir("/dev/cgroup/perf_event/blah");
        sleep(2);
        perf_event_open(&attr, fd, 0, -1,  PERF_FLAG_PID_CGROUP);
        perror("perf_event_open");
        close(fd);
        return 0;
 }

Signed-off-by: Salman Qazi <sqazi@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20120614223108.1025.2503.stgit@dungbeetle.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 11:45:57 +02:00
Ingo Molnar
4983955c04 Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
Pull ftrace robustization fixes from Steve Rostedt.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-18 10:57:51 +02:00
Yuanhan Liu
b56a39ac26 printk: return -EINVAL if the message len is bigger than the buf size
Just like what devkmsg_read() does, return -EINVAL if the message len is
bigger than the buf size, or it will trigger a segfault error.

Acked-by: Kay Sievers <kay@vrfy.org>
Acked-by: Fengguang Wu <wfg@linux.intel.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-16 08:36:03 -07:00
Yuanhan Liu
4a77a5a06e printk: use mutex lock to stop syslog_seq from going wild
Although syslog_seq and log_next_seq stuff are protected by logbuf_lock
spin log, it's not enough. Say we have two processes A and B, and let
syslog_seq = N, while log_next_seq = N + 1, and the two processes both
come to syslog_print at almost the same time. And No matter which
process get the spin lock first, it will increase syslog_seq by one,
then release spin lock; thus later, another process increase syslog_seq
by one again. In this case, syslog_seq is bigger than syslog_next_seq.
And latter, it would make:
   wait_event_interruptiable(log_wait, syslog != log_next_seq)
don't wait any more even there is no new write comes. Thus it introduce
a infinite loop reading.

I can easily see this kind of issue by the following steps:
  # cat /proc/kmsg # at meantime, I don't kill rsyslog
                   # So they are the two processes.
  # xinit          # I added drm.debug=6 in the kernel parameter line,
                   # so that it will produce lots of message and let that
                   # issue happen

It's 100% reproducable on my side. And my disk will be filled up by
/var/log/messages in a quite short time.

So, introduce a mutex_lock to stop syslog_seq from going wild just like
what devkmsg_read() does. It does fix this issue as expected.

v2: use mutex_lock_interruptiable() instead (comments from Kay)

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-By: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-16 08:36:02 -07:00
Oleg Nesterov
e227051b13 uprobes: Remove the unnecessary initialization in add_utask()
Trivial cleanup. No need to nullify ->active_uprobe after
kzalloc().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120615154401.GA9633@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:52 +02:00
Oleg Nesterov
593609a596 uprobes: __copy_insn() needs "loff_t offset"
1. __copy_insn() needs "loff_t offset", not "unsigned long",
   to read the file.

2. use pgoff_t for "idx" and remove the unnecessary typecast.

3. fix the typo, "&=" is not what we want

4. can't resist, rename off1 to off.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154359.GA9625@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:49 +02:00
Oleg Nesterov
816c03fbab uprobes: Don't use loff_t for the valid virtual address
loff_t looks confusing when it is used for the virtual address.
Change map_info and install_breakpoint/remove_breakpoint paths
to use "unsigned long".

The patch doesn't change vma_address(), it can't return "long"
because it is used to verify the mapping. But probably this
needs some cleanups too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154355.GA9622@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:48 +02:00
Oleg Nesterov
449d0d7c9f uprobes: Simplify the usage of uprobe->pending_list
uprobe->pending_list is only used to create the temporary list,
it has no meaning after we drop uprobes_mmap_hash(inode).

No need to initialize this node or remove it from tmp_list, and
we can use list_for_each_entry().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120615154353.GA9614@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:48 +02:00
Oleg Nesterov
d9c4a30e82 uprobes: Move BUG_ON(UPROBE_SWBP_INSN_SIZE) from write_opcode() to install_breakpoint()
write_opcode() ensures that UPROBE_SWBP_INSN doesn't cross the
page boundary. This looks a bit confusing, the check does not
depend on vaddr and it is enough to do it only once right after
install_breakpoint()->arch_uprobe_analyze_insn().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154350.GA9611@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:47 +02:00
Oleg Nesterov
eb2bf57bee uprobes: No need to re-check vma_address() in write_opcode()
write_opcode() is called by register_for_each_vma() and
uprobe_mmap() paths. In both cases the caller has already
verified this vaddr under mmap_sem, no need to re-check.

Note also that this check is wrong anyway, we should not
truncate loff_t returned by vma_address() if we do not trust
this mapping.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154347.GA9604@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:47 +02:00
Oleg Nesterov
fc36f59565 uprobes: Copy_insn() should not return -ENOMEM if __copy_insn() fails
copy_insn() returns -ENOMEM if the first __copy_insn() fails,
it should return the correct error code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154344.GA9601@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:46 +02:00
Oleg Nesterov
d436615e60 uprobes: Copy_insn() shouldn't depend on mm/vma/vaddr
1. copy_insn() doesn't need "addr", it can use uprobe->offset.
   Remove this argument.

2. Change copy_insn/__copy_insn to accept "struct file*" instead
   of vma.

copy_insn() is called only once and mm/vma/vaddr are random, it
shouldn't depend on them.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154342.GA9598@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:45 +02:00
Peter Zijlstra
c5784de2b3 uprobes: Document uprobe_register() vs uprobe_mmap() race
Because the mind is treacherous and makes us forget we need to
write stuff down.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20120615154339.GA9591@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:45 +02:00
Oleg Nesterov
7a5bfb66b0 uprobes: Change build_map_info() to try kmalloc(GFP_NOWAIT) first
build_map_info() doesn't allocate the memory under i_mmap_mutex
to avoid the deadlock with page reclaim. But it can try
GFP_NOWAIT first, it should work in the likely case and thus we
almost never need the pre-alloc-and-retry path.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120615154336.GA9588@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:44 +02:00
Oleg Nesterov
268720903f uprobes: Rework register_for_each_vma() to make it O(n)
Currently register_for_each_vma() is O(n ** 2) + O(n ** 3),
every time find_next_vma_info() "restarts" the
vma_prio_tree_foreach() loop and each iteration rechecks the
whole try_list. This also means that try_list can grow
"indefinitely" if register/unregister races with munmap/mmap
activity even if the number of mapping is bounded at any time.

With this patch register_for_each_vma() builds the list of
mm/vaddr structures only once and does install_breakpoint() for
each entry.

We do not care about the new mappings which can be created after
build_map_info() drops mapping->i_mmap_mutex, uprobe_mmap()
should do its work.

Note that we do not allocate map_info under i_mmap_mutex, this
can deadlock with page reclaim (but see the next patch). So we
use 2 lists, "curr" which we are going to return, and "prev"
which holds the already allocated memory. The main loop deques
the entry from "prev" (initially it is empty), and if "prev"
becomes empty again it counts the number of entries we need to
pre-allocate outside of i_mmap_mutex.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120615154333.GA9581@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:43 +02:00
Oleg Nesterov
c1914a0936 uprobes: Install_breakpoint() should fail if is_swbp_insn() == T
install_breakpoint() returns -EEXIST if is_swbp_insn(orig_insn)
== T, the caller treats this code as success.

This is doubly wrong. The successful return should set
UPROBE_COPY_INSN, but the real problem is that it shouldn't
succeed. If the probed insn is int3 the application should get
SIGTRAP, this won't happen with uprobe.

Probably we can fix this, we can add the UPROBE_SHARED_BP flag
and teach handle_swbp/set_orig_insn to handle this case
correctly. But this needs some complications and we have other
insns which can't be probed, lets make a simple fix for now.

I think this needs a cleanup. UPROBE_COPY_INSN should die,
copy_insn() should be called by alloc_uprobe().
arch_uprobe_analyze_insn() depends on ->mm (ia32_compat) but it
is called only once.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154331.GA9578@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:43 +02:00
Oleg Nesterov
5323ce71e4 uprobes: Write_opcode()->__replace_page() can race with try_to_unmap()
write_opcode() gets old_page via get_user_pages() and then calls
__replace_page() which assumes that this old_page is still
mapped after pte_offset_map_lock().

This is not true if this old_page was already try_to_unmap()'ed,
and in this case everything __replace_page() does with old_page
is wrong. Just for example, put_page() is not balanced.

I think it is possible to teach __replace_page() to handle this
unlikely case correctly, but this patch simply changes it to use
page_check_address() and return -EAGAIN if it fails. The caller
should notice this error code and retry.

Note: write_opcode() asks for the cleanups, I'll try to do this
in a separate patch.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154328.GA9571@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:42 +02:00
Oleg Nesterov
cc359d180f uprobes: __copy_insn() should ensure a_ops->readpage != NULL
__copy_insn() blindly calls read_mapping_page(), this will crash
the kernel if ->readpage == NULL, add the necessary check. For
example, hugetlbfs_aops->readpage is NULL. Perhaps we should
change read_mapping_page() instead.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154325.GA9568@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:42 +02:00
Oleg Nesterov
ea13137714 uprobes: Valid_vma() should reject VM_HUGETLB
__replace_page() obviously can't work with the hugetlbfs
mappings, uprobe_register() will likely crash the kernel. Change
valid_vma() to check VM_HUGETLB as well.

As for PageTransHuge() no need to worry, vma->vm_file != NULL.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120615154322.GA9561@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-16 09:10:41 +02:00
Linus Torvalds
ed21a66c18 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar.

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  watchdog: Quiet down the boot messages
  perf/x86: Fix broken LBR fixup code
  tracing: Have tracing_off() actually turn tracing off
2012-06-15 16:58:10 -07:00
Linus Torvalds
a95f9b6e09 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core updates (RCU and locking) from Ingo Molnar:
 "Most of the diffstat comes from the RCU slow boot regression fixes,
  but there's also a debuggability improvements/fixes."

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  memblock: Document memblock_is_region_{memory,reserved}()
  rcu: Precompute RCU_FAST_NO_HZ timer offsets
  rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure
  rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks
  rcu: RCU_FAST_NO_HZ detection of callback adoption
  spinlock: Indicate that a lockup is only suspected
  kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop()
  panic: Make panic_on_oops configurable
2012-06-15 16:52:35 -07:00
Kay Sievers
e2ae715d66 kmsg - kmsg_dump() use iterator to receive log buffer content
Provide an iterator to receive the log buffer content, and convert all
kmsg_dump() users to it.

The structured data in the kmsg buffer now contains binary data, which
should no longer be copied verbatim to the kmsg_dump() users.

The iterator should provide reliable access to the buffer data, and also
supports proper log line-aware chunking of data while iterating.

Signed-off-by: Kay Sievers <kay@vrfy.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Reported-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Tested-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-15 14:53:59 -07:00
Steven Rostedt
7374e82771 tracing: Register the ftrace internal events during early boot
All trace events including ftrace internel events (like trace_printk
and function tracing), register functions that describe how to print
their output. The events may be recorded as soon as the ring buffer
is allocated, but they are just raw binary in the buffer. The mapping
of event ids to how to print them are held within a structure that
is registered on system boot.

If a crash happens in boot up before these functions are registered
then their output (via ftrace_dump_on_oops) will be useless:

Dumping ftrace buffer:
---------------------------------
   <...>-1       0.... 319705us : Unknown type 6
---------------------------------

This can be quite frustrating for a kernel developer trying to see
what is going wrong.

There's no reason to register them so late in the boot up process.
They can be registered by early_initcall().

Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-14 15:22:14 -04:00
Borislav Petkov
8d240dd88c ftrace: Remove a superfluous check
register_ftrace_function() checks ftrace_disabled and calls
__register_ftrace_function which does it again.

Drop the first check and add the unlikely hint to the second one. Also,
drop the label as John correctly notices.

No functional change.

Link: http://lkml.kernel.org/r/20120329171140.GE6409@aftab

Cc: Borislav Petkov <bp@amd64.org>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-14 15:22:12 -04:00
Don Zickus
a702704682 watchdog: Quiet down the boot messages
A bunch of bugzillas have complained how noisy the nmi_watchdog
is during boot-up especially with its expected failure cases
(like virt and bios resource contention).

This is my attempt to quiet them down and keep it less confusing
for the end user.  What I did is print the message for cpu0 and
save it for future comparisons.  If future cpus have an
identical message as cpu0, then don't print the redundant info.
However, if a future cpu has a different message, happily print
that loudly.

Before the change, you would see something like:

    ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
    CPU0: Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz stepping 0a
    Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
    ... version:                2
    ... bit width:              40
    ... generic registers:      2
    ... value mask:             000000ffffffffff
    ... max period:             000000007fffffff
    ... fixed-purpose events:   3
    ... event mask:             0000000700000003
    NMI watchdog enabled, takes one hw-pmu counter.
    Booting Node   0, Processors  #1
    NMI watchdog enabled, takes one hw-pmu counter.
     #2
    NMI watchdog enabled, takes one hw-pmu counter.
     #3 Ok.
    NMI watchdog enabled, takes one hw-pmu counter.
    Brought up 4 CPUs
    Total of 4 processors activated (22607.24 BogoMIPS).

After the change, it is simplified to:

    ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
    CPU0: Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz stepping 0a
    Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
    ... version:                2
    ... bit width:              40
    ... generic registers:      2
    ... value mask:             000000ffffffffff
    ... max period:             000000007fffffff
    ... fixed-purpose events:   3
    ... event mask:             0000000700000003
    NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
    Booting Node   0, Processors  #1 #2 #3 Ok.
    Brought up 4 CPUs

V2: little changes based on Joe Perches' feedback
V3: printk cleanup based on Ingo's feedback; checkpatch fix
V4: keep printk as one long line
V5: Ingo fix ups

Reported-and-tested-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: nzimmer@sgi.com
Cc: joe@perches.com
Link: http://lkml.kernel.org/r/1339594548-17227-1-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-14 12:20:50 +02:00
Yinghai Lu
82ec90eac3 resources: allow adjust_resource() for resources with no parent
If a resource has no parent, allow its start/end to be set arbitrarily
as long as any children are still contained within the new range.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-06-13 15:42:22 -06:00
Eric Dumazet
047fe36052 splice: fix racy pipe->buffers uses
Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()

commit 35f3d14dbb (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.

Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.

Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.

splice_shrink_spd() loses its struct pipe_inode_info argument.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.35
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-06-13 21:16:42 +02:00
Andrew Lunn
6ebb017de9 printk: Fix alignment of buf causing crash on ARM EABI
Commit 7ff9554bb5, printk: convert
byte-buffer to variable-length record buffer, causes systems using
EABI to crash very early in the boot cycle. The first entry in struct
log is a u64, which for EABI must be 8 byte aligned.

Make use of __alignof__() so the compiler to decide the alignment, but
allow it to be overridden using CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
for systems which can perform unaligned access and want to save
a few bytes of space.

Tested on Orion5x and Kirkwood.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-12 16:20:17 -07:00
Thomas Gleixner
924412f66f Merge branch 'nohz-for-tip-2' of git://github.com/fweisbec/linux-dynticks into timers/core 2012-06-11 20:11:29 +02:00
Frederic Weisbecker
84bf1bccc6 nohz: Move next idle expiry time record into idle logic area
The next idle expiry time record and idle sleeps tracking are
statistics that only concern idle.

Since we want the nohz APIs to become usable further idle
context, let's pull up the handling of these statistics to the
callers in idle.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 20:07:18 +02:00
Frederic Weisbecker
5b39939a40 nohz: Move ts->idle_calls incrementation into strict idle logic
Since we want to prepare for making the nohz API to work further
the idle case, we need to pull ts->idle_calls incrementation up to
the callers in idle.

To perform this, we split tick_nohz_stop_sched_tick() in two parts:
a first one that checks if we can really stop the tick for idle,
and another that actually stops it. Then from the callers in idle,
we check if we can stop the tick and only then we increment idle_calls
and finally relay to the nohz API that won't care about these details
anymore.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 20:07:17 +02:00
Frederic Weisbecker
f5d411c91e nohz: Rename ts->idle_tick to ts->last_tick
Now that idle and nohz logics are going to be independant each others,
ts->idle_tick becomes too much a biased name to describe the field that
saves the last scheduled tick on top of which we re-calculate the next
tick to schedule when the timer is restarted.

We want to reuse this even to stop the tick outside idle cases. So let's
rename it to some more generic name: ts->last_tick.

This changes a bit the timer list stat export so we need to increase its
version.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 20:07:17 +02:00
Frederic Weisbecker
2ac0d98fd6 nohz: Make nohz API agnostic against idle ticks cputime accounting
When the timer tick fires, it accounts the new jiffy as either part
of system, user or idle time. This is how we record the cputime
statistics.

But when the tick is stopped from the idle task, we still need
to record the number of jiffies spent tickless until we restart
the tick and fall back to traditional tick-based cputime accounting.

To do this, we take a snapshot of jiffies when the tick is stopped
and compute the difference against the new value of jiffies when
the tick is restarted. Then we account this whole difference to
the idle cputime.

However we are preparing to be able to stop the tick from other places
than idle. So this idle time accounting needs to be performed from
the callers of nohz APIs, not from the nohz APIs themselves because
we now want them to be agnostic against places that stop/restart tick.

Therefore, we pull the tickless idle time accounting out of generic
nohz helpers up to idle entry/exit callers.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 20:07:16 +02:00
Frederic Weisbecker
19f5f7364a nohz: Separate idle sleeping time accounting from nohz logic
As we plan to be able to stop the tick outside the idle task, we
need to prepare for separating nohz logic from idle. As a start,
this pulls the idle sleeping time accounting out of the tick
stop/restart API to the callers on idle entry/exit.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 20:06:36 +02:00
Thomas Gleixner
b871a42b60 smpboot: Remove leftover declaration
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-06-11 15:07:52 +02:00
Ingo Molnar
c3e228d59b Linux 3.5-rc2
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Merge tag 'v3.5-rc2' into perf/core

Merge in Linux 3.5-rc2 - to pick up fixes.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-11 10:51:35 +02:00
Ingo Molnar
4a1e001d2b Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent
Merge RCU fixes from Paul E. McKenney:

 " This series has four patches, the major point of which is to eliminate
   some slowdowns (including boot-time slowdowns) resulting from some
   RCU_FAST_NO_HZ changes.  The issue with the changes is that posting timers
   from the idle loop has no effect if the CPU has entered dyntick-idle
   mode because the CPU has already computed its wakeup time, and posting
   a timer does not cause it to be recomputed.  The short-term fix is for
   RCU to precompute the timeout value so that the CPU's calculation is
   correct. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-11 10:30:23 +02:00
Linus Torvalds
7249450449 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar.

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix the relax_domain_level boot parameter
  sched: Validate assumptions in sched_init_numa()
  sched: Always initialize cpu-power
  sched: Fix domain iteration
  sched/rt: Fix lockdep annotation within find_lock_lowest_rq()
  sched/numa: Load balance between remote nodes
  sched/x86: Calculate booted cores after construction of sibling_mask
2012-06-08 14:59:29 -07:00
Randy Dunlap
cd96891d48 sched/fair: fix lots of kernel-doc warnings
Fix lots of new kernel-doc warnings in kernel/sched/fair.c:

  Warning(kernel/sched/fair.c:3625): No description found for parameter 'env'
  Warning(kernel/sched/fair.c:3625): Excess function parameter 'sd' description in 'update_sg_lb_stats'
  Warning(kernel/sched/fair.c:3735): No description found for parameter 'env'
  Warning(kernel/sched/fair.c:3735): Excess function parameter 'sd' description in 'update_sd_pick_busiest'
  Warning(kernel/sched/fair.c:3735): Excess function parameter 'this_cpu' description in 'update_sd_pick_busiest'
  .. more warnings

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-08 14:59:10 -07:00
Linus Torvalds
106544d81d Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "A bit larger than what I'd wish for - half of it is due to hw driver
  updates to Intel Ivy-Bridge which info got recently released,
  cycles:pp should work there now too, amongst other things.  (but we
  are generally making exceptions for hardware enablement of this type.)

  There are also callchain fixes in it - responding to mostly
  theoretical (but valid) concerns.  The tooling side sports perf.data
  endianness/portability fixes which did not make it for the merge
  window - and various other fixes as well."

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  perf/x86: Check user address explicitly in copy_from_user_nmi()
  perf/x86: Check if user fp is valid
  perf: Limit callchains to 127
  perf/x86: Allow multiple stacks
  perf/x86: Update SNB PEBS constraints
  perf/x86: Enable/Add IvyBridge hardware support
  perf/x86: Implement cycles:p for SNB/IVB
  perf/x86: Fix Intel shared extra MSR allocation
  x86/decoder: Fix bsr/bsf/jmpe decoding with operand-size prefix
  perf: Remove duplicate invocation on perf_event_for_each
  perf uprobes: Remove unnecessary check before strlist__delete
  perf symbols: Check for valid dso before creating map
  perf evsel: Fix 32 bit values endianity swap for sample_id_all header
  perf session: Handle endianity swap on sample_id_all header data
  perf symbols: Handle different endians properly during symbol load
  perf evlist: Pass third argument to ioctl explicitly
  perf tools: Update ioctl documentation for PERF_IOC_FLAG_GROUP
  perf tools: Make --version show kernel version instead of pull req tag
  perf tools: Check if callchain is corrupted
  perf callchain: Make callchain cursors TLS
  ...
2012-06-08 09:14:46 -07:00
Linus Torvalds
b1e25f4109 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull leap second timer fix from Thomas Gleixner.

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
2012-06-08 09:11:33 -07:00
Ingo Molnar
9ee6ddc9da Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent
Pull brown paper bag fix from Steve Rostedt.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-08 12:23:22 +02:00
Ananth N Mavinakayanahalli
7eb9ba5ed3 uprobes: Pass probed vaddr to arch_uprobe_analyze_insn()
On RISC architectures like powerpc, instructions are fixed size.
Instruction analysis on such platforms is just a matter of
(insn % 4). Pass the vaddr at which the uprobe is to be inserted so
that arch_uprobe_analyze_insn() can flag misaligned registration
requests.

Signed-off-by: Ananth N Mavinakaynahalli <ananth@in.ibm.com>
Cc: michael@ellerman.id.au
Cc: antonb@thinktux.localdomain
Cc: Paul Mackerras <paulus@samba.org>
Cc: benh@kernel.crashing.org
Cc: peterz@infradead.org
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: oleg@redhat.com
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20120608093257.GG13409@in.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-08 12:22:27 +02:00
Linus Torvalds
48d212a2ee Revert "mm: correctly synchronize rss-counters at exit/exec"
This reverts commit 40af1bbdca.

It's horribly and utterly broken for at least the following reasons:

 - calling sync_mm_rss() from mmput() is fundamentally wrong, because
   there's absolutely no reason to believe that the task that does the
   mmput() always does it on its own VM.  Example: fork, ptrace, /proc -
   you name it.

 - calling it *after* having done mmdrop() on it is doubly insane, since
   the mm struct may well be gone now.

 - testing mm against NULL before you call it is insane too, since a
NULL mm there would have caused oopses long before.

.. and those are just the three bugs I found before I decided to give up
looking for me and revert it asap.  I should have caught it before I
even took it, but I trusted Andrew too much.

Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 17:54:07 -07:00
Konstantin Khlebnikov
40af1bbdca mm: correctly synchronize rss-counters at exit/exec
mm->rss_stat counters have per-task delta: task->rss_stat.  Before
changing task->mm pointer the kernel must flush this delta with
sync_mm_rss().

do_exit() already calls sync_mm_rss() to flush the rss-counters before
committing the rss statistics into task->signal->maxrss, taskstats,
audit and other stuff.  Unfortunately the kernel does this before
calling mm_release(), which can call put_user() for processing
task->clear_child_tid.  So at this point we can trigger page-faults and
task->rss_stat becomes non-zero again.  As a result mm->rss_stat becomes
inconsistent and check_mm() will print something like this:

| BUG: Bad rss-counter state mm:ffff88020813c380 idx:1 val:-1
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:2 val:1

This patch moves sync_mm_rss() into mm_release(), and moves mm_release()
out of do_exit() and calls it earlier.  After mm_release() there should
be no pagefaults.

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>		[3.4.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
Cyrill Gorcunov
736f24d5e5 c/r: prctl: drop VMA flags test on PR_SET_MM_ stack data assignment
In commit b76437579d ("procfs: mark thread stack correctly in
proc/<pid>/maps") the stack allocated via clone() is marked in
/proc/<pid>/maps as [stack:%d] thus it might be out of the former
mm->start_stack/end_stack values (and even has some custom VMA flags
set).

So to be able to restore mm->start_stack/end_stack drop vma flags test,
but still require the underlying VMA to exist.

As always note this feature is under CONFIG_CHECKPOINT_RESTORE and
requires CAP_SYS_RESOURCE to be granted.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
Cyrill Gorcunov
300f786b26 c/r: prctl: add ability to get clear_tid_address
Zero is written at clear_tid_address when the process exits.  This
functionality is used by pthread_join().

We already have sys_set_tid_address() to change this address for the
current task but there is no way to obtain it from user space.

Without the ability to find this address and dump it we can't restore
pthread'ed apps which call pthread_join() once they have been restored.

This patch introduces the PR_GET_TID_ADDRESS prctl option which allows
the current process to obtain own clear_tid_address.

This feature is available iif CONFIG_CHECKPOINT_RESTORE is set.

[akpm@linux-foundation.org: fix prctl numbering]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pedro Alves <palves@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
Cyrill Gorcunov
1ad75b9e16 c/r: prctl: add minimal address test to PR_SET_MM
Make sure the address being set is greater than mmap_min_addr (as
suggested by Kees Cook).

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
Konstantin Khlebnikov
bafb282df2 c/r: prctl: update prctl_set_mm_exe_file() after mm->num_exe_file_vmas removal
A fix for commit b32dfe3771 ("c/r: prctl: add ability to set new
mm_struct::exe_file").

After removing mm->num_exe_file_vmas kernel keeps mm->exe_file until
final mmput(), it never becomes NULL while task is alive.

We can check for other mapped files in mm instead of checking
mm->num_exe_file_vmas, and mark mm with flag MMF_EXE_FILE_CHANGED in
order to forbid second changing of mm->exe_file.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
Paul E. McKenney
aa9b16306e rcu: Precompute RCU_FAST_NO_HZ timer offsets
When a CPU is entering dyntick-idle mode, tick_nohz_stop_sched_tick()
calls rcu_needs_cpu() see if RCU needs that CPU, and, if not, computes the
next wakeup time based on the timer wheels.  Only later, when actually
entering the idle loop, rcu_prepare_for_idle() will be invoked.  In some
cases, rcu_prepare_for_idle() will post timers to wake the CPU back up.
But all for naught: The next wakeup time for the CPU has already been
computed, and posting a timer afterwards does not force that wakeup
time to be recomputed.  This means that rcu_prepare_for_idle()'s have
no effect.

This is not a problem on a busy system because something else will wake
up the CPU soon enough.  However, on lightly loaded systems, the CPU
might stay asleep for a considerable length of time.  If that CPU has
a callback that the rest of the system is waiting on, the system might
run very slowly or (in theory) even hang.

This commit avoids this problem by having rcu_needs_cpu() give
tick_nohz_stop_sched_tick() an estimate of when RCU will need the CPU
to wake back up, which tick_nohz_stop_sched_tick() takes into account
when programming the CPU's wakeup time.  An alternative approach is
for rcu_prepare_for_idle() to use hrtimers instead of normal timers,
but timers are much more efficient than are hrtimers for frequently
and repeatedly posting and cancelling a given timer, which is exactly
what RCU_FAST_NO_HZ does.

Reported-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
2012-06-06 20:43:28 -07:00
Paul E. McKenney
5955f7eecd rcu: Move RCU_FAST_NO_HZ per-CPU variables to rcu_dynticks structure
The RCU_FAST_NO_HZ code relies on a number of per-CPU variables.
This works, but is hidden from someone scanning the data structures
in rcutree.h.  This commit therefore converts these per-CPU variables
to fields in the per-CPU rcu_dynticks structures.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
2012-06-06 20:43:28 -07:00
Paul E. McKenney
fd4b352687 rcu: Update RCU_FAST_NO_HZ tracing for lazy callbacks
In the current code, a short dyntick-idle interval (where there is
at least one non-lazy callback on the CPU) and a long dyntick-idle
interval (where there are only lazy callbacks on the CPU) are traced
identically, which can be less than helpful.  This commit therefore
emits different event traces in these two cases.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
2012-06-06 20:43:27 -07:00
Paul E. McKenney
8f5af6f1f2 rcu: RCU_FAST_NO_HZ detection of callback adoption
In the present implementations of CPU hotplug, the outgoing CPU is
guaranteed to run its stop-machine process on the way out, which
will guarantee that RCU_FAST_NO_HZ forces the CPU out of dyntick-idle
mode.

However, new versions of CPU hotplug might not work this way.  This
commit therefore removes this design constraint by explicitly notifying
CPUs when they adopt non-lazy RCU callbacks.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Pascal Chapperon <pascal.chapperon@wanadoo.fr>
2012-06-06 20:43:27 -07:00
Steven Rostedt
f2bf1f6f5f tracing: Have tracing_off() actually turn tracing off
A recent update to have tracing_on/off() only affect the ftrace ring
buffers instead of all ring buffers had a cut and paste error.
The tracing_off() did the exact same thing as tracing_on() and
would not actually turn off tracing. Unfortunately, tracing_off()
is more important to be working than tracing_on() as this is a key
development tool, as it lets the developer turn off tracing as soon
as a problem is discovered. It is also used by panic and oops code.

This bug also breaks the 'echo func:traceoff > set_ftrace_filter'

Cc: <stable@vger.kernel.org> # 3.4
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-06-06 22:15:14 -04:00
Li Zefan
6be96a5c90 cgroup: remove hierarchy_mutex
It was introduced for memcg to iterate cgroup hierarchy without
holding cgroup_mutex, but soon after that it was replaced with
a lockless way in memcg.

No one used hierarchy_mutex since that, so remove it.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2012-06-06 19:12:30 -07:00
Salman Qazi
967db0ea65 cgroup: make sure that decisions in __css_put are atomic
__css_put is using atomic_dec on the ref count, and then
looking at the ref count to make decisions.  This is prone
to races, as someone else may decrement ref count between
our decrement and our decision.  Instead, we should base our
decisions on the value that we decremented the ref count to.

(This results in an actual race on Google's kernel which I
haven't been able to reproduce on the upstream kernel.  Having
said that, it's still incorrect by inspection).

Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
2012-06-06 18:51:35 -07:00
Oleg Nesterov
778b032d96 uprobes: Kill uprobes_srcu/uprobe_srcu_id
Kill the no longer needed uprobes_srcu/uprobe_srcu_id code.

It doesn't really work anyway. synchronize_srcu() can only
synchronize with the code "inside" the
srcu_read_lock/srcu_read_unlock section, while
uprobe_pre_sstep_notifier() does srcu_read_lock() _after_ we
already hit the breakpoint.

I guess this probably works "in practice". synchronize_srcu() is
slow and it implies synchronize_sched(), and the probed task
enters the non- preemptible section at the start of exception
handler. Still this is not right at least in theory, and
task->uprobe_srcu_id blows task_struct.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529193008.GG8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:22:22 +02:00
Oleg Nesterov
56bb4cf647 uprobes: Teach handle_swbp() to rely on "is_swbp" rather than uprobes_srcu
Currently handle_swbp() assumes that it can't race with
unregister, so it roughly does:

	if (find_uprobe(vaddr))
		process_uprobe();
	else
		send_sig(SIGTRAP);

This relies on the not-really-working uprobes_srcu code we are
going to remove, see the next patch.

With this patch we rely on the result of
is_swbp_at_addr(bp_vaddr) if find_uprobe() fails.

If is_swbp == 1, then we hit the normal int3, we should send
SIGTRAP.

If is_swbp == 0, we raced with uprobe_unregister(), we simply
restart this insn again.

The "difficult" case is is_swbp == -EFAULT, when we can't read
this memory. In this case I think we should restart too, and
this is more correct compared to the current code which sends
SIGTRAP.

Ignoring ENOMEM/etc from get_user_pages(), this can only happen
if another thread unmaps this memory before find_active_uprobe()
takes mmap_sem. It would be better to pretend it was unmapped
before this insn was executed, restart, and get SIGSEGV.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192947.GF8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:22:03 +02:00
Oleg Nesterov
77fc4af1b5 uprobes: Change register_for_each_vma() to take mm->mmap_sem for writing
Change register_for_each_vma() to take mm->mmap_sem for writing.
This is a bit unfortunate but hopefully not too bad, this is the
slow path anyway.

This is needed to ensure that find_active_uprobe() can not race
with uprobe_register() which adds the new bp at the same
bp_vaddr, after find_uprobe() fails and before
is_swbp_at_addr_fast() checks the memory.

IOW, this is needed to ensure that if find_active_uprobe()
returns NULL but is_swbp == true, we can safely assume that it
was the "normal" int3 and we should send SIGTRAP.

There is another reason for this change. We are going to replace
uprobes_state->count with MMF_ flags set by register/unregister
and cleared by find_active_uprobe(), and set/clear shouldn't
race with each other.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192928.GE8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:21:48 +02:00
Oleg Nesterov
d790d34653 uprobes: Teach find_active_uprobe() to provide the "is_swbp" info
A separate patch to simplify the review, and for the
documentation.

The patch adds another "int *is_swbp" argument to
find_active_uprobe(), so far its only caller doesn't use this
info.

With this patch find_active_uprobe() additionally does:

	- if find_vma() + ->vm_start check fails, *is_swbp = -EFAULT

	- otherwise, if valid_vma() + find_uprobe() fails, it holds
	  the result of is_swbp_at_addr(), can be negative too. The
	  latter is only possible if we raced with another thread
	  which did munmap/etc after we hit this bp.

IOW. If find_active_uprobe(&is_swbp) returns NULL, the caller
can look at is_swbp to figure out whether the current insn is bp
or not, or detect the race with another thread if it is
negative.

Note: I think that performance-wise this change is fine. This
adds is_swbp_at_addr(), but only if we raced with
uprobe_unregister() or if we hit the "normal" int3 but this mm
has uprobes as well. And even in this case the slow
read_opcode() path is very unlikely, this insn recently
triggered do_int3(), __copy_from_user_inatomic() shouldn't fail
in the likely case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192914.GD8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:15:24 +02:00
Oleg Nesterov
3a9ea0520f uprobes: Introduce find_active_uprobe() helper
No functional changes. Move the "find uprobe" code from
handle_swbp() to the new helper, find_active_uprobe().

Note: with or without this change, the find-active-uprobe logic
is not exactly right. We can race with another thread which
unmaps the memory with the valid uprobe before we take
mm->mmap_sem. We can't find this uprobe simply because
find_vma() fails. In this case we wrongly assume that this trap
was not caused by uprobe and send the erroneous SIGTRAP. See the
next changes.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192857.GC8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:15:17 +02:00
Oleg Nesterov
a3d7bb4793 uprobes: Change read_opcode() to use FOLL_FORCE
set_orig_insn()->read_opcode() should not fail if the probed
task did mprotect() after uprobe_register(), change it to use
FOLL_FORCE. Without FOLL_WRITE this doesn't have any "side"
effect but allows to read the !VM_READ memory.

There is another reason for this change, we are going to use
is_swbp_at_addr() from handle_swbp() which can race with another
thread doing mprotect().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192759.GB8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:14:49 +02:00
Oleg Nesterov
c00b275043 uprobes: Optimize is_swbp_at_addr() for current->mm
Change is_swbp_at_addr() to try to avoid the costly
read_opcode() if mm == current->mm, __copy_from_user_inatomic()
should succeed in the likely case.

Currently this optimization is not important, but we are going
to add more is_swbp_at_addr(current->mm) callers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192744.GA8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:13:59 +02:00
Dimitri Sivanich
a841f8cef4 sched: Fix the relax_domain_level boot parameter
It does not get processed because sched_domain_level_max is 0 at the
time that setup_relax_domain_level() is run.

Simply accept the value as it is, as we don't know the value of
sched_domain_level_max until sched domain construction is completed.

Fix sched_relax_domain_level in cpuset.  The build_sched_domain() routine calls
the set_domain_attribute() routine prior to setting the sd->level, however,
the set_domain_attribute() routine relies on the sd->level to decide whether
idle load balancing will be off/on.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120605184436.GA15668@sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 17:07:41 +02:00
Peter Zijlstra
d039ac6080 sched: Validate assumptions in sched_init_numa()
Add some code to validate assumptions we're making and output
warnings if they are not.

If this trigger we want to know about it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alex Shi <lkml.alex@gmail.com>
Link: http://lkml.kernel.org/n/tip-6uc3wk5s9udxtdl9cnku0vtt@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 16:52:30 +02:00
Peter Zijlstra
c3decf0dfb sched: Always initialize cpu-power
Often when we run into mis-shapen topologies the balance iteration
fails to update the cpu power properly and we'll end up in /0 traps.

Always initialize the cpu-power to a semi-sane value so that we can
at least boot the machine, even if the load-balancer might not
function correctly.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-3lbhyj25sr169ha7z3qht5na@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 16:52:27 +02:00
Peter Zijlstra
c117487687 sched: Fix domain iteration
Weird topologies can lead to asymmetric domain setups. This needs
further consideration since these setups are typically non-minimal
too.

For now, make it work by adding an extra mask selecting which CPUs
are allowed to iterate up.

The topology that triggered it is the one from David Rientjes:

	10 20 20 30
	20 10 20 20
	20 20 10 20
	30 20 20 10

resulting in boxes that wouldn't even boot.

Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-3p86l9cuaqnxz7uxsojmz5rm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 16:52:26 +02:00
Peter Zijlstra
7f1b43936f sched/rt: Fix lockdep annotation within find_lock_lowest_rq()
Roland Dreier reported spurious, hard to trigger lockdep warnings
within the scheduler - without any real lockup.

This bit gives us the right clue:

> [89945.640512]  [<ffffffff8103fa1a>] double_lock_balance+0x5a/0x90
> [89945.640568]  [<ffffffff8104c546>] push_rt_task+0xc6/0x290

if you look at that code you'll find the double_lock_balance() in
question is the one in find_lock_lowest_rq() [yay for inlining].

Now find_lock_lowest_rq() has a bug.. it fails to use
double_unlock_balance() in one exit path, if this results in a retry in
push_rt_task() we'll call double_lock_balance() again, at which point
we'll run into said lockdep confusion.

Reported-by: Roland Dreier <roland@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1337282386.4281.77.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 16:52:26 +02:00
Alex Shi
10717dcde1 sched/numa: Load balance between remote nodes
Commit cb83b629b ("sched/numa: Rewrite the CONFIG_NUMA sched
domain support") removed the NODE sched domain and started checking
if the node distance in SLIT table is farther than REMOTE_DISTANCE,
if so, it will lose the load balance chance at exec/fork/wake_affine
points.

But actually, even the node distance is farther than REMOTE_DISTANCE.

Modern CPUs also has QPI like connections, which ensures that memory
access is not too slow between nodes. So the above change in behavior
on NUMA machine causes a performance regression on various benchmarks:
hackbench, tbench, netperf, oltp, etc.

This patch will recover the scheduler behavior to old mode on all my
Intel platforms: NHM EP/EX, WSM EP, SNB EP/EP4S, and thus fixes the
perfromance regressions. (all of them just have 2 kinds distance, 10, 21)

Signed-off-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338965571-9812-1-git-send-email-alex.shi@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 16:52:25 +02:00
Thomas Gleixner
e40468a548 timers: Improve get_next_timer_interrupt()
Gilad reported at

 http://lkml.kernel.org/r/1336056962-10465-2-git-send-email-gilad@benyossef.com

"Current timer code fails to correctly return a value meaning that
 there is no future timer event, with the result that the timer keeps
 getting re-armed in HZ one shot mode even when we could turn it off,
 generating unneeded interrupts.

 What is happening is that when __next_timer_interrupt() wishes
 to return a value that signifies "there is no future timer
 event", it returns (base->timer_jiffies + NEXT_TIMER_MAX_DELTA).

 However, the code in tick_nohz_stop_sched_tick(), which called
 __next_timer_interrupt() via get_next_timer_interrupt(),
 compares the return value to (last_jiffies + NEXT_TIMER_MAX_DELTA)
 to see if the timer needs to be re-armed.

 base->timer_jiffies != last_jiffies and so tick_nohz_stop_sched_tick()
 interperts the return value as indication that there is a distant
 future event 12 days from now and programs the timer to fire next
 after KTIME_MAX nsecs instead of avoiding to arm it. This ends up
 causing a needless interrupt once every KTIME_MAX nsecs."

Fix this by using the new active timer accounting. This avoids scans
when no active timer is enqueued completely, so we don't have to rely
on base->timer_next and base->timer_jiffies anymore.

Reported-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20120525214819.317535385@linutronix.de
2012-06-06 13:49:02 +02:00
Thomas Gleixner
99d5f3aac6 timers: Add accounting of non deferrable timers
The code in get_next_timer_interrupt() is suboptimal as it has to run
through the cascade to find the next expiring timer. On a completely
idle core we should only do that when there is an active timer
enqueued and base->next_timer does not give us a fast answer.

Add accounting of the active timers to the now consolidated
attach/detach code. I deliberately avoided sanity checks because the
code is fully symetric and any fiddling with timers w/o using the API
functions will lead to cute explosions anyway. ulong is big enough
even on 32bit and if we really run into the situation to have more
than 1<<32 timers enqueued there, then we are definitely not in a
state to go idle and run through that code.

This allows us to fix another shortcoming of get_next_timer_interrupt().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20120525214819.236377028@linutronix.de
2012-06-06 13:49:01 +02:00
Thomas Gleixner
facbb4a7ef timers: Consolidate base->next_timer update
Another bunch of mindlessly copied code. All callers of
internal_add_timer() except the recascading code updates
base->next_timer.

Move this into internal_add_timer() and let the cascading code call
__internal_add_timer().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20120525214819.189946224@linutronix.de
2012-06-06 13:49:01 +02:00
Thomas Gleixner
ec44bc7acc timers: Create detach_if_pending() and use it
Most callers of detach_timer() have the same pattern around
them. Check whether the timer is pending and eventually updating
base->next_timer.

Create detach_if_pending() and replace the duplicated code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20120525214819.131246037@linutronix.de
2012-06-06 13:49:01 +02:00
Ingo Molnar
c7f5f4ab10 Merge branch 'core/debug' into core/urgent
Merge two debugging patchlets that were waiting for
preparatory commits to hit upstream.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 11:12:55 +02:00
Ingo Molnar
02e03040a3 Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf fixes from Arnaldo Carvalho de Melo:

 * Endianness fixes from Jiri Olsa

 * Fixes for make perf tarball

 * Fix for DSO name in perf script callchains, from David Ahern

 * Segfault fixes for perf top --callchain, from Namhyung Kim

 * Minor function result fixes from Srikar Dronamraju

 * Add missing 3rd ioctl parameter, from Namhyung Kim

 * Fix pager usage in minimal embedded systems, from Avik Sil

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 08:46:33 +02:00
Linus Torvalds
365f0e173f Merge branch 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
 "This fixes the possible premature superblock release on umount bug
  mentioned during v3.5-rc1 pull request.

  Originally, cgroup dentry destruction path assumed that cgroup dentry
  didn't have any reference left after cgroup removal thus put super
  during dentry removal.  Now that there can be lingering dentry
  references, this led to super being put with live dentries.  This
  patch fixes the problem by putting super ref on dentry release instead
  of removal."

* 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: superblock can't be released with active dentries
2012-06-05 11:54:12 -07:00
Linus Torvalds
0b3e9f3f21 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar.

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Remove NULL assignment of dattr_cur
  sched: Remove the last NULL entry from sched_feat_names
  sched: Make sched_feat_names const
  sched/rt: Fix SCHED_RR across cgroups
  sched: Move nr_cpus_allowed out of 'struct sched_rt_entity'
  sched: Make sure to not re-read variables after validation
  sched: Fix SD_OVERLAP
  sched: Don't try allocating memory from offline nodes
  sched/nohz: Fix rq->cpu_load calculations some more
  sched/x86: Use cpu_llc_shared_mask(cpu) for coregroup_mask
2012-06-05 09:47:15 -07:00
Yong Zhang
8feb8e896d smp: Remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]()
There is no user of those APIs anymore, just remove it.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: ralf@linux-mips.org
Cc: sshtylyov@mvista.com
Cc: david.daney@cavium.com
Cc: nikunj@linux.vnet.ibm.com
Cc: paulmck@linux.vnet.ibm.com
Cc: axboe@kernel.dk
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1338275765-3217-11-git-send-email-yong.zhang0@gmail.com
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-06-05 17:27:14 +02:00
John Stultz
fad0c66c4b timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
Commit 6b43ae8a61 (ntp: Fix leap-second hrtimer livelock) broke the
leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to
wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC.

Adjust wall_to_monotonic when NTP inserted a leapsecond.

Reported-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Richard Cochran <richardcochran@gmail.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1338400497-12420-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-06-04 21:46:29 +02:00
Linus Torvalds
9171c670b4 Merge branches 'irq-urgent-for-linus' and 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq and smpboot updates from Thomas Gleixner:
 "Just cleanup patches with no functional change and a fix for suspend
  issues."

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Introduce irq_do_set_affinity() to reduce duplicated code
  genirq: Add IRQS_PENDING for nested and simple irq

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smpboot, idle: Fix comment mismatch over idle_threads_init()
  smpboot, idle: Optimize calls to smp_processor_id() in idle_threads_init()
2012-06-04 11:36:51 -07:00
Linus Torvalds
c22072bdf0 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "The clocksource driver is pure hardware enablement and the skew option
  is default off, well tested and non dangerous."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: Move skew_tick option into the HIGH_RES_TIMER section
  clocksource: em_sti: Add DT support
  clocksource: em_sti: Emma Mobile STI driver
  clockevents: Make clockevents_config() a global symbol
  tick: Add tick skew boot option
2012-06-04 11:25:31 -07:00
Linus Torvalds
86c47b70f6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull third pile of signal handling patches from Al Viro:
 "This time it's mostly helpers and conversions to them; there's a lot
  of stuff remaining in the tree, but that'll either go in -rc2
  (isolated bug fixes, ideally via arch maintainers' trees) or will sit
  there until the next cycle."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  x86: get rid of calling do_notify_resume() when returning to kernel mode
  blackfin: check __get_user() return value
  whack-a-mole with TIF_FREEZE
  FRV: Optimise the system call exit path in entry.S [ver #2]
  FRV: Shrink TIF_WORK_MASK [ver #2]
  FRV: Prevent syscall exit tracing and notify_resume at end of kernel exceptions
  new helper: signal_delivered()
  powerpc: get rid of restore_sigmask()
  most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set
  set_restore_sigmask() is never called without SIGPENDING (and never should be)
  TIF_RESTORE_SIGMASK can be set only when TIF_SIGPENDING is set
  don't call try_to_freeze() from do_signal()
  pull clearing RESTORE_SIGMASK into block_sigmask()
  sh64: failure to build sigframe != signal without handler
  openrisc: tracehook_signal_handler() is supposed to be called on success
  new helper: sigmask_to_save()
  new helper: restore_saved_sigmask()
  new helpers: {clear,test,test_and_clear}_restore_sigmask()
  HAVE_RESTORE_SIGMASK is defined on all architectures now
2012-06-01 11:53:44 -07:00
Linus Torvalds
1193755ac6 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs changes from Al Viro.
 "A lot of misc stuff.  The obvious groups:
   * Miklos' atomic_open series; kills the damn abuse of
     ->d_revalidate() by NFS, which was the major stumbling block for
     all work in that area.
   * ripping security_file_mmap() and dealing with deadlocks in the
     area; sanitizing the neighborhood of vm_mmap()/vm_munmap() in
     general.
   * ->encode_fh() switched to saner API; insane fake dentry in
     mm/cleancache.c gone.
   * assorted annotations in fs (endianness, __user)
   * parts of Artem's ->s_dirty work (jff2 and reiserfs parts)
   * ->update_time() work from Josef.
   * other bits and pieces all over the place.

  Normally it would've been in two or three pull requests, but
  signal.git stuff had eaten a lot of time during this cycle ;-/"

Fix up trivial conflicts in Documentation/filesystems/vfs.txt (the
'truncate_range' inode method was removed by the VM changes, the VFS
update adds an 'update_time()' method), and in fs/btrfs/ulist.[ch] (due
to sparse fix added twice, with other changes nearby).

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (95 commits)
  nfs: don't open in ->d_revalidate
  vfs: retry last component if opening stale dentry
  vfs: nameidata_to_filp(): don't throw away file on error
  vfs: nameidata_to_filp(): inline __dentry_open()
  vfs: do_dentry_open(): don't put filp
  vfs: split __dentry_open()
  vfs: do_last() common post lookup
  vfs: do_last(): add audit_inode before open
  vfs: do_last(): only return EISDIR for O_CREAT
  vfs: do_last(): check LOOKUP_DIRECTORY
  vfs: do_last(): make ENOENT exit RCU safe
  vfs: make follow_link check RCU safe
  vfs: do_last(): use inode variable
  vfs: do_last(): inline walk_component()
  vfs: do_last(): make exit RCU safe
  vfs: split do_lookup()
  Btrfs: move over to use ->update_time
  fs: introduce inode operation ->update_time
  reiserfs: get rid of resierfs_sync_super
  reiserfs: mark the superblock as dirty a bit later
  ...
2012-06-01 10:34:35 -07:00
Al Viro
efee984c27 new helper: signal_delivered()
Does block_sigmask() + tracehook_signal_handler();  called when
sigframe has been successfully built.  All architectures converted
to it; block_sigmask() itself is gone now (merged into this one).

I'm still not too happy with the signature, but that's a separate
story (IMO we need a structure that would contain signal number +
siginfo + k_sigaction, so that get_signal_to_deliver() would fill one,
signal_delivered(), handle_signal() and probably setup...frame() -
take one).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:52 -04:00
Al Viro
77097ae503 most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set
Only 3 out of 63 do not.  Renamed the current variant to __set_current_blocked(),
added set_current_blocked() that will exclude unblockable signals, switched
open-coded instances to it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:51 -04:00
Al Viro
a610d6e672 pull clearing RESTORE_SIGMASK into block_sigmask()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:49 -04:00
Al Viro
754421c8ca HAVE_RESTORE_SIGMASK is defined on all architectures now
Everyone either defines it in arch thread_info.h or has TIF_RESTORE_SIGMASK
and picks default set_restore_sigmask() in linux/thread_info.h.  Kill the
ifdefs, slap #error in linux/thread_info.h to catch breakage when new ones
get merged.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:46 -04:00
Linus Torvalds
fb21affa49 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull second pile of signal handling patches from Al Viro:
 "This one is just task_work_add() series + remaining prereqs for it.

  There probably will be another pull request from that tree this
  cycle - at least for helpers, to get them out of the way for per-arch
  fixes remaining in the tree."

Fix trivial conflict in kernel/irq/manage.c: the merge of Andrew's pile
had brought in commit 97fd75b7b8 ("kernel/irq/manage.c: use the
pr_foo() infrastructure to prefix printks") which changed one of the
pr_err() calls that this merge moves around.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  keys: kill task_struct->replacement_session_keyring
  keys: kill the dummy key_replace_session_keyring()
  keys: change keyctl_session_to_parent() to use task_work_add()
  genirq: reimplement exit_irq_thread() hook via task_work_add()
  task_work_add: generic process-context callbacks
  avr32: missed _TIF_NOTIFY_RESUME on one of do_notify_resume callers
  parisc: need to check NOTIFY_RESUME when exiting from syscall
  move key_repace_session_keyring() into tracehook_notify_resume()
  TIF_NOTIFY_RESUME is defined on all targets now
2012-05-31 18:47:30 -07:00
Linus Torvalds
08615d7d85 Merge branch 'akpm' (Andrew's patch-bomb)
Merge misc patches from Andrew Morton:

 - the "misc" tree - stuff from all over the map

 - checkpatch updates

 - fatfs

 - kmod changes

 - procfs

 - cpumask

 - UML

 - kexec

 - mqueue

 - rapidio

 - pidns

 - some checkpoint-restore feature work.  Reluctantly.  Most of it
   delayed a release.  I'm still rather worried that we don't have a
   clear roadmap to completion for this work.

* emailed from Andrew Morton <akpm@linux-foundation.org>: (78 patches)
  kconfig: update compression algorithm info
  c/r: prctl: add ability to set new mm_struct::exe_file
  c/r: prctl: extend PR_SET_MM to set up more mm_struct entries
  c/r: procfs: add arg_start/end, env_start/end and exit_code members to /proc/$pid/stat
  syscalls, x86: add __NR_kcmp syscall
  fs, proc: introduce /proc/<pid>/task/<tid>/children entry
  sysctl: make kernel.ns_last_pid control dependent on CHECKPOINT_RESTORE
  aio/vfs: cleanup of rw_copy_check_uvector() and compat_rw_copy_check_uvector()
  eventfd: change int to __u64 in eventfd_signal()
  fs/nls: add Apple NLS
  pidns: make killed children autoreap
  pidns: use task_active_pid_ns in do_notify_parent
  rapidio/tsi721: add DMA engine support
  rapidio: add DMA engine support for RIO data transfers
  ipc/mqueue: add rbtree node caching support
  tools/selftests: add mq_perf_tests
  ipc/mqueue: strengthen checks on mqueue creation
  ipc/mqueue: correct mq_attr_ok test
  ipc/mqueue: improve performance of send/recv
  selftests: add mq_open_tests
  ...
2012-05-31 18:10:18 -07:00
Cyrill Gorcunov
b32dfe3771 c/r: prctl: add ability to set new mm_struct::exe_file
When we do restore we would like to have a way to setup a former
mm_struct::exe_file so that /proc/pid/exe would point to the original
executable file a process had at checkpoint time.

For this the PR_SET_MM_EXE_FILE code is introduced.  This option takes a
file descriptor which will be set as a source for new /proc/$pid/exe
symlink.

Note it allows to change /proc/$pid/exe if there are no VM_EXECUTABLE
vmas present for current process, simply because this feature is a special
to C/R and mm::num_exe_file_vmas become meaningless after that.

To minimize the amount of transition the /proc/pid/exe symlink might have,
this feature is implemented in one-shot manner.  Thus once changed the
symlink can't be changed again.  This should help sysadmins to monitor the
symlinks over all process running in a system.

In particular one could make a snapshot of processes and ring alarm if
there unexpected changes of /proc/pid/exe's in a system.

Note -- this feature is available iif CONFIG_CHECKPOINT_RESTORE is set and
the caller must have CAP_SYS_RESOURCE capability granted, otherwise the
request to change symlink will be rejected.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
Cyrill Gorcunov
fe8c7f5cbf c/r: prctl: extend PR_SET_MM to set up more mm_struct entries
During checkpoint we dump whole process memory to a file and the dump
includes process stack memory.  But among stack data itself, the stack
carries additional parameters such as command line arguments, environment
data and auxiliary vector.

So when we do restore procedure and once we've restored stack data itself
we need to setup mm_struct::arg_start/end, env_start/end, so restored
process would be able to find command line arguments and environment data
it had at checkpoint time.  The same applies to auxiliary vector.

For this reason additional PR_SET_MM_(ARG_START | ARG_END | ENV_START |
ENV_END | AUXV) codes are introduced.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
Cyrill Gorcunov
d97b46a646 syscalls, x86: add __NR_kcmp syscall
While doing the checkpoint-restore in the user space one need to determine
whether various kernel objects (like mm_struct-s of file_struct-s) are
shared between tasks and restore this state.

The 2nd step can be solved by using appropriate CLONE_ flags and the
unshare syscall, while there's currently no ways for solving the 1st one.

One of the ways for checking whether two tasks share e.g.  mm_struct is to
provide some mm_struct ID of a task to its proc file, but showing such
info considered to be not that good for security reasons.

Thus after some debates we end up in conclusion that using that named
'comparison' syscall might be the best candidate.  So here is it --
__NR_kcmp.

It takes up to 5 arguments - the pids of the two tasks (which
characteristics should be compared), the comparison type and (in case of
comparison of files) two file descriptors.

Lookups for pids are done in the caller's PID namespace only.

At moment only x86 is supported and tested.

[akpm@linux-foundation.org: fix up selftests, warnings]
[akpm@linux-foundation.org: include errno.h]
[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: Michal Marek <mmarek@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
Cyrill Gorcunov
98ed57eef9 sysctl: make kernel.ns_last_pid control dependent on CHECKPOINT_RESTORE
For those who doesn't need C/R functionality there is no need to control
last pid, ie the pid for the next fork() call.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
Eric W. Biederman
00c10bc13c pidns: make killed children autoreap
Force SIGCHLD handling to SIG_IGN so that signals are not generated and so
that the children autoreap.  This increases the parallelize and in general
the speed of network namespace shutdown.

Note self reaping childrean can exist past zap_pid_ns_processess but they
will all be reaped before we allow the pid namespace init task with pid ==
1 to be reaped.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:32 -07:00
Eric W. Biederman
3208450488 pidns: use task_active_pid_ns in do_notify_parent
Using task_active_pid_ns is more robust because it works even after we
have called exit_namespaces.  This change allows us to have parent
processes that are zombies.  Normally a zombie parent processes is crazy
and the last thing you would want to have but in the case of not letting
the init process of a pid namespace be reaped until all of it's children
are dead and reaped a zombie parent process is exactly what we want.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:31 -07:00
Anton Vorontsov
e4cc2f873a kernel/cpu.c: document clear_tasks_mm_cpumask()
Add more comments on clear_tasks_mm_cpumask, plus adds a runtime check:
the function is only suitable for offlined CPUs, and if called
inappropriately, the kernel should scream aloud.

[akpm@linux-foundation.org: tweak comment: s/walks up/walks/, use 80 cols]
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:30 -07:00
Anton Vorontsov
cb79295e20 cpu: introduce clear_tasks_mm_cpumask() helper
Many architectures clear tasks' mm_cpumask like this:

	read_lock(&tasklist_lock);
	for_each_process(p) {
		if (p->mm)
			cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
	}
	read_unlock(&tasklist_lock);

Depending on the context, the code above may have several problems,
such as:

1. Working with task->mm w/o getting mm or grabing the task lock is
   dangerous as ->mm might disappear (exit_mm() assigns NULL under
   task_lock(), so tasklist lock is not enough).

2. Checking for process->mm is not enough because process' main
   thread may exit or detach its mm via use_mm(), but other threads
   may still have a valid mm.

This patch implements a small helper function that does things
correctly, i.e.:

1. We take the task's lock while whe handle its mm (we can't use
   get_task_mm()/mmput() pair as mmput() might sleep);

2. To catch exited main thread case, we use find_lock_task_mm(),
   which walks up all threads and returns an appropriate task
   (with task lock held).

Also, Per Peter Zijlstra's idea, now we don't grab tasklist_lock in
the new helper, instead we take the rcu read lock. We can do this
because the function is called after the cpu is taken down and marked
offline, so no new tasks will get this cpu set in their mm mask.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:29 -07:00
Konstantin Khlebnikov
f7505d64f2 fork: call complete_vfork_done() after clearing child_tid and flushing rss-counters
Child should wake up the parent from vfork() only after finishing all
operations with shared mm.  There is no sense in using
CLONE_CHILD_CLEARTID together with CLONE_VFORK, but it looks more accurate
now.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:29 -07:00
Tim Bird
168eeccbc9 stack usage: add pid to warning printk in check_stack_usage
In embedded systems, sometimes the same program (busybox) is the cause of
multiple warnings.  Outputting the pid with the program name in the
warning printk helps distinguish which instances of a program are using
the stack most.

This is a small patch, but useful.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Oleg Nesterov
43e13cc107 cred: remove task_is_dead() from __task_cred() validation
Commit 8f92054e7c ("CRED: Fix __task_cred()'s lockdep check and banner
comment"):

    add the following validation condition:

        task->exit_state >= 0

    to permit the access if the target task is dead and therefore
    unable to change its own credentials.

OK, but afaics currently this can only help wait_task_zombie() which calls
__task_cred() without rcu lock.

Remove this validation and change wait_task_zombie() to use task_uid()
instead.  This means we do rcu_read_lock() only to shut up the lockdep,
but we already do the same in, say, wait_task_stopped().

task_is_dead() should die, task->exit_state != 0 means that this task has
passed exit_notify(), only do_wait-like code paths should use this.

Unfortunately, we can't kill task_is_dead() right now, it has already
acquired buggy users in drivers/staging.  The fix already exists.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Randy Dunlap
9b3c98cd66 kmod.c: fix kernel-doc warning
Warning(kernel/kmod.c:419): No description found for parameter 'depth'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Boaz Harrosh
785042f2e2 kmod: move call_usermodehelper_fns() to .c file and unexport all it's helpers
If we move call_usermodehelper_fns() to kmod.c file and EXPORT_SYMBOL it
we can avoid exporting all it's helper functions:
	call_usermodehelper_setup
	call_usermodehelper_setfns
	call_usermodehelper_exec
And make all of them static to kmod.c

Since the optimizer will see all these as a single call site it will
inline them inside call_usermodehelper_fns().  So we loose the call to
_fns but gain 3 calls to the helpers.  (Not that it matters)

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Boaz Harrosh
81ab6e7b26 kmod: convert two call sites to call_usermodehelper_fns()
Both kernel/sys.c && security/keys/request_key.c where inlining the exact
same code as call_usermodehelper_fns(); So simply convert these sites to
directly use call_usermodehelper_fns().

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Boaz Harrosh
ae3cef7300 kmod: unexport call_usermodehelper_freeinfo()
call_usermodehelper_freeinfo() is not used outside of kmod.c.  So unexport
it, and make it static to kmod.c

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:28 -07:00
Nicolas Pitre
d84970bbaf kernel/cpu_pm.c: fix various typos
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Colin Cross <ccross@android.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:27 -07:00
Andrew Morton
97fd75b7b8 kernel/irq/manage.c: use the pr_foo() infrastructure to prefix printks
Use the module-wide pr_fmt() mechanism rather than open-coding "genirq: "
everywhere.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:26 -07:00
Sasikantha babu
499eea6bf9 sethostname/setdomainname: notify userspace when there is a change in uts_kern_table
sethostname() and setdomainname() notify userspace on failure (without
modifying uts_kern_table).  Change things so that we only notify userspace
on success, when uts_kern_table was actually modified.

Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: WANG Cong <amwang@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:26 -07:00
Wei Yang
ee5e5683d8 kernel/resource.c: correct the comment of allocate_resource()
In the comment of allocate_resource(), the explanation of parameter max
and min is not correct.

Actually, these two parameters are used to specify the range of the
resource that will be allocated, not the min/max size that will be
allocated.

Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:26 -07:00
Namhyung Kim
cb7225feec perf: Remove duplicate invocation on perf_event_for_each
The @func callback was invoked twice for group leader when
perf_event_for_each() called. It seems the commit 75f937f24b
("perf_counter: Fix ctx->mutex vs counter ->mutex inversion") made the
mistake during the change.

Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338443506-25009-1-git-send-email-namhyung.kim@lge.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-05-31 14:01:00 -03:00
Linus Torvalds
65a50c951a Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar.

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  perf ui browser: Stop using 'self'
  perf annotate browser: Read perf config file for settings
  perf config: Allow '_' in config file variable names
  perf annotate browser: Make feature toggles global
  perf annotate browser: The idx_asm field should be used in asm only view
  perf tools: Convert critical messages to ui__error()
  perf ui: Make --stdio default when TUI is not supported
  tools lib traceevent: Silence compiler warning on 32bit build
  perf record: Fix branch_stack type in perf_record_opts
  perf tools: Reconstruct event with modifiers from perf_event_attr
  perf top: Fix counter name fixup when fallbacking to cpu-clock
  perf tools: fix thread_map__new_by_pid_str() memory leak in error path
  perf tools: Do not use _FORTIFY_SOURCE when DEBUG=1 is specified
  tools lib traceevent: Fix signature of create_arg_item()
  tools lib traceevent: Use proper function parameter type
  tools lib traceevent: Fix freeing arg on process_dynamic_array()
  tools lib traceevent: Fix a possibly wrong memory dereference
  tools lib traceevent: Fix a possible memory leak
  tools lib traceevent: Allow expressions in __print_symbolic() fields
  perf evlist: Explicititely initialize input_name
  ...
2012-05-30 11:12:00 -07:00
Linus Torvalds
0d167518e0 Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block
Merge block/IO core bits from Jens Axboe:
 "This is a bit bigger on the core side than usual, but that is purely
  because we decided to hold off on parts of Tejun's submission on 3.4
  to give it a bit more time to simmer.  As a consequence, it's seen a
  long cycle in for-next.

  It contains:

   - Bug fix from Dan, wrong locking type.
   - Relax splice gifting restriction from Eric.
   - A ton of updates from Tejun, primarily for blkcg.  This improves
     the code a lot, making the API nicer and cleaner, and also includes
     fixes for how we handle and tie policies and re-activate on
     switches.  The changes also include generic bug fixes.
   - A simple fix from Vivek, along with a fix for doing proper delayed
     allocation of the blkcg stats."

Fix up annoying conflict just due to different merge resolution in
Documentation/feature-removal-schedule.txt

* 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits)
  blkcg: tg_stats_alloc_lock is an irq lock
  vmsplice: relax alignement requirements for SPLICE_F_GIFT
  blkcg: use radix tree to index blkgs from blkcg
  blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
  block: fix elvpriv allocation failure handling
  block: collapse blk_alloc_request() into get_request()
  blkcg: collapse blkcg_policy_ops into blkcg_policy
  blkcg: embed struct blkg_policy_data in policy specific data
  blkcg: mass rename of blkcg API
  blkcg: style cleanups for blk-cgroup.h
  blkcg: remove blkio_group->path[]
  blkcg: blkg_rwstat_read() was missing inline
  blkcg: shoot down blkgs if all policies are deactivated
  blkcg: drop stuff unused after per-queue policy activation update
  blkcg: implement per-queue policy activation
  blkcg: add request_queue->root_blkg
  blkcg: make request_queue bypassing on allocation
  blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
  blkcg: make blkg_conf_prep() take @pol and return with queue lock held
  blkcg: remove static policy ID enums
  ...
2012-05-30 08:52:42 -07:00
Kamalesh Babulal
6a4c96eef4 sched: Remove NULL assignment of dattr_cur
Remove explicit NULL assignment of static pointer
dattr_cur from init_sched_domains().

Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120523091411.GG5005@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:27 +02:00
Hiroshi Shimamoto
7997a456ef sched: Remove the last NULL entry from sched_feat_names
No need to have the last NULL entry.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4FBF29E7.5020805@ct.jp.nec.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:27 +02:00
Hiroshi Shimamoto
1292531f6f sched: Make sched_feat_names const
The strings sched_feat_names are never changed.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4FBF29B2.9030904@ct.jp.nec.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:26 +02:00
Colin Cross
454c79999f sched/rt: Fix SCHED_RR across cgroups
task_tick_rt() has an optimization to only reschedule SCHED_RR tasks
if they were the only element on their rq.  However, with cgroups
a SCHED_RR task could be the only element on its per-cgroup rq but
still be competing with other SCHED_RR tasks in its parent's
cgroup.  In this case, the SCHED_RR task in the child cgroup would
never yield at the end of its timeslice.  If the child cgroup
rt_runtime_us was the same as the parent cgroup rt_runtime_us,
the task in the parent cgroup would starve completely.

Modify task_tick_rt() to check that the task is the only task on its
rq, and that the each of the scheduling entities of its ancestors
is also the only entity on its rq.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1337229266-15798-1-git-send-email-ccross@android.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:25 +02:00
Peter Zijlstra
29baa7478b sched: Move nr_cpus_allowed out of 'struct sched_rt_entity'
Since nr_cpus_allowed is used outside of sched/rt.c and wants to be
used outside of there more, move it to a more natural site.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kr61f02y9brwzkh6x53pdptm@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:25 +02:00
Peter Zijlstra
b654f7de41 sched: Make sure to not re-read variables after validation
We could re-read rq->rt_avg after we validated it was smaller than
total, invalidating the check and resulting in an unintended negative.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1337688268.9698.29.camel@twins
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:24 +02:00
Peter Zijlstra
74a5ce20e6 sched: Fix SD_OVERLAP
SD_OVERLAP exists to allow overlapping groups, overlapping groups
appear in NUMA topologies that aren't fully connected.

The typical result of not fully connected NUMA is that each cpu (or
rather node) will have different spans for a particular distance.
However due to how sched domains are traversed -- only the first cpu
in the mask goes one level up -- the next level only cares about the
spans of the cpus that went up.

Due to this two things were observed to be broken:

 - build_overlap_sched_groups() -- since its possible the cpu we're
   building the groups for exists in multiple (or all) groups, the
   selection criteria of the first group didn't ensure there was a cpu
   for which is was true that cpumask_first(span) == cpu. Thus load-
   balancing would terminate.

 - update_group_power() -- assumed that the cpu span of the first
   group of the domain was covered by all groups of the child domain.
   The above explains why this isn't true, so deal with it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/1337788843.9783.14.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:24 +02:00
Peter Zijlstra
2ea45800d8 sched: Don't try allocating memory from offline nodes
Allocators don't appreciate it when you try and allocate memory from
offline nodes.

Reported-and-tested-by: Tony Luck <tony.luck@intel.com>
Reported-and-tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-epfc1io9whb7o22bcujf31vn@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:23 +02:00
Peter Zijlstra
5aaa0b7a2e sched/nohz: Fix rq->cpu_load calculations some more
Follow up on commit 556061b00 ("sched/nohz: Fix rq->cpu_load[]
calculations") since while that fixed the busy case it regressed the
mostly idle case.

Add a callback from the nohz exit to also age the rq->cpu_load[]
array. This closes the hole where either there was no nohz load
balance pass during the nohz, or there was a 'significant' amount of
idle time between the last nohz balance and the nohz exit.

So we'll update unconditionally from the tick to not insert any
accidental 0 load periods while busy, and we try and catch up from
nohz idle balance and nohz exit. Both these are still prone to missing
a jiffy, but that has always been the case.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: pjt@google.com
Cc: Venkatesh Pallipadi <venki@google.com>
Link: http://lkml.kernel.org/n/tip-kt0trz0apodbf84ucjfdbr1a@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 14:02:16 +02:00
Ingo Molnar
063e047761 Merge branch 'linus' into perf/urgent
Merge back Linus's latest branch so that we pick up the uprobes changes.

( I tested this branch locally and while it's one from the middle of the
  merge window it's a good one to base further work off. )

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-05-30 10:59:04 +02:00
Andi Kleen
eea62f831b brlocks/lglocks: turn into functions
lglocks and brlocks are currently generated with some complicated macros
in lglock.h.  But there's no reason to not just use common utility
functions and put all the data into a common data structure.

Since there are at least two users it makes sense to share this code in a
library.  This is also easier maintainable than a macro forest.

This will also make it later possible to dynamically allocate lglocks and
also use them in modules (this would both still need some additional, but
now straightforward, code)

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29 23:28:41 -04:00
Stephen Boyd
4796dd200d vsprintf: fix %ps on non symbols when using kallsyms
Using %ps in a printk format will sometimes fail silently and print the
empty string if the address passed in does not match a symbol that
kallsyms knows about.  But using %pS will fall back to printing the full
address if kallsyms can't find the symbol.  Make %ps act the same as %pS
by falling back to printing the address.

While we're here also make %ps print the module that a symbol comes from
so that it matches what %pS already does.  Take this simple function for
example (in a module):

	static void test_printk(void)
	{
		int test;
		pr_info("with pS: %pS\n", &test);
		pr_info("with ps: %ps\n", &test);
	}

Before this patch:

 with pS: 0xdff7df44
 with ps:

After this patch:

 with pS: 0xdff7df44
 with ps: 0xdff7df44

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:32 -07:00
Frederic Weisbecker
2bb2ba9d51 rescounters: add res_counter_uncharge_until()
When killing a res_counter which is a child of other counter, we need to
do

	res_counter_uncharge(child, xxx)
	res_counter_charge(parent, xxx)

This is not atomic and wastes CPU.  This patch adds
res_counter_uncharge_until().  This function's uncharge propagates to
ancestors until specified res_counter.

	res_counter_uncharge_until(child, parent, xxx)

Now the operation is atomic and efficient.

Signed-off-by: Frederic Weisbecker <fweisbec@redhat.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Johannes Weiner
91c63734f6 kernel: cgroup: push rcu read locking from css_is_ancestor() to callsite
Library functions should not grab locks when the callsites can do it,
even if the lock nests like the rcu read-side lock does.

Push the rcu_read_lock() from css_is_ancestor() to its single user,
mem_cgroup_same_or_subtree() in preparation for another user that may
already hold the rcu read-side lock.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:20 -07:00
Siddhesh Poyarekar
7edc8b0ac1 mm/fork: fix overflow in vma length when copying mmap on clone
The vma length in dup_mmap is calculated and stored in a unsigned int,
which is insufficient and hence overflows for very large maps (beyond
16TB). The following program demonstrates this:

#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>

#define GIG 1024 * 1024 * 1024L
#define EXTENT 16393

int main(void)
{
        int i, r;
        void *m;
        char buf[1024];

        for (i = 0; i < EXTENT; i++) {
                m = mmap(NULL, (size_t) 1 * 1024 * 1024 * 1024L,
                         PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);

                if (m == (void *)-1)
                        printf("MMAP Failed: %d\n", m);
                else
                        printf("%d : MMAP returned %p\n", i, m);

                r = fork();

                if (r == 0) {
                        printf("%d: successed\n", i);
                        return 0;
                } else if (r < 0)
                        printf("FORK Failed: %d\n", r);
                else if (r > 0)
                        wait(NULL);
        }
        return 0;
}

Increase the storage size of the result to unsigned long, which is
sufficient for storing the difference between addresses.

Signed-off-by: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:19 -07:00
Rik van Riel
e709ffd616 mm: remove swap token code
The swap token code no longer fits in with the current VM model.  It
does not play well with cgroups or the better NUMA placement code in
development, since we have only one swap token globally.

It also has the potential to mess with scalability of the system, by
increasing the number of non-reclaimable pages on the active and
inactive anon LRU lists.

Last but not least, the swap token code has been broken for a year
without complaints, as reported by Konstantin Khlebnikov.  This suggests
we no longer have much use for it.

The days of sub-1G memory systems with heavy use of swap are over.  If
we ever need thrashing reducing code in the future, we will have to
implement something that does scale.

Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Bob Picco <bpicco@meloft.net>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:19 -07:00
Tejun Heo
fa980ca87d cgroup: superblock can't be released with active dentries
48ddbe1946 "cgroup: make css->refcnt clearing on cgroup removal
optional" allowed a css to linger after the associated cgroup is
removed.  As a css holds a reference on the cgroup's dentry, it means
that cgroup dentries may linger for a while.

cgroup_create() does grab an active reference on the superblock to
prevent it from going away while there are !root cgroups; however, the
reference is put from cgroup_diput() which is invoked on cgroup
removal, so cgroup dentries which are removed but persisting due to
lingering csses already have released their superblock active refs
allowing superblock to be killed while those dentries are around.

Given the right condition, this makes cgroup_kill_sb() call
kill_litter_super() with dentries with non-zero d_count leading to
BUG() in shrink_dcache_for_umount_subtree().

Fix it by adding cgroup_dops->d_release() operation and moving
deactivate_super() to it.  cgroup_diput() now marks dentry->d_fsdata
with itself if superblock should be deactivated and cgroup_d_release()
deactivates the superblock on dentry release.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
LKML-Reference: <CA+1xoqe5hMuxzCRhMy7J0XchDk2ZnuxOHJKikROk1-ReAzcT6g@mail.gmail.com>
Acked-by: Li Zefan <lizefan@huawei.com>
2012-05-27 17:22:56 -07:00
Thomas Gleixner
62cf20b32a tick: Move skew_tick option into the HIGH_RES_TIMER section
commit 5307c95 (tick: Add tick skew boot option) broke the
!CONFIG_HIGH_RES_TIMERS build.

Move the boot option parsing into the CONFIG_HIGH_RES_TIMERS section.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <mgalbraith@suse.de>
2012-05-25 14:08:57 +02:00
Magnus Damm
e5400321a6 clockevents: Make clockevents_config() a global symbol
Make clockevents_config() into a global symbol to allow it to be used
by compiled-in clockevent drivers. This is needed by drivers that want
to update the timer frequency after registration time.

Signed-off-by: Magnus Damm <damm@opensource.se>
Tested-by: Simon Horman <horms@verge.net.au>
Cc: arnd@arndb.de
Cc: johnstul@us.ibm.com
Cc: rjw@sisk.pl
Cc: lethal@linux-sh.org
Cc: gregkh@linuxfoundation.org
Cc: olof@lixom.net
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20120509143934.27521.46553.sendpatchset@w520
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-25 01:44:51 +02:00
Mike Galbraith
5307c9556b tick: Add tick skew boot option
Let the user decide whether power consumption or jitter is the
more important consideration for their machines.

Quoting removal commit af5ab277de:

"Historically, Linux has tried to make the regular timer tick on the
 various CPUs not happen at the same time, to avoid contention on
 xtime_lock.
    
 Nowadays, with the tickless kernel, this contention no longer happens
 since time keeping and updating are done differently. In addition,
 this skew is actually hurting power consumption in a measurable way on
 many-core systems."

Problems:

- Contrary to the above, systems do encounter contention on both
  xtime_lock and RCU structure locks when the tick is synchronized.
  
- Moderate sized RT systems suffer intolerable jitter due to the tick
  being synchronized.

- SGI reports the same for their large systems.

- Fully utilized systems reap no power saving benefit from skew removal,
  but do suffer from resulting induced lock contention.

- 0209f649 rcu: limit rcu_node leaf-level fanout
  This patch was born to combat lock contention which testing showed
  to have been _induced by_ skew removal.  Skew the tick, contention
  disappeared virtually completely.

Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
Link: http://lkml.kernel.org/r/1336472458.21924.78.camel@marge.simpson.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-25 01:44:50 +02:00
Linus Torvalds
07acfc2a93 Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM changes from Avi Kivity:
 "Changes include additional instruction emulation, page-crossing MMIO,
  faster dirty logging, preventing the watchdog from killing a stopped
  guest, module autoload, a new MSI ABI, and some minor optimizations
  and fixes.  Outside x86 we have a small s390 and a very large ppc
  update.

  Regarding the new (for kvm) rebaseless workflow, some of the patches
  that were merged before we switch trees had to be rebased, while
  others are true pulls.  In either case the signoffs should be correct
  now."

Fix up trivial conflicts in Documentation/feature-removal-schedule.txt
arch/powerpc/kvm/book3s_segment.S and arch/x86/include/asm/kvm_para.h.

I suspect the kvm_para.h resolution ends up doing the "do I have cpuid"
check effectively twice (it was done differently in two different
commits), but better safe than sorry ;)

* 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (125 commits)
  KVM: make asm-generic/kvm_para.h have an ifdef __KERNEL__ block
  KVM: s390: onereg for timer related registers
  KVM: s390: epoch difference and TOD programmable field
  KVM: s390: KVM_GET/SET_ONEREG for s390
  KVM: s390: add capability indicating COW support
  KVM: Fix mmu_reload() clash with nested vmx event injection
  KVM: MMU: Don't use RCU for lockless shadow walking
  KVM: VMX: Optimize %ds, %es reload
  KVM: VMX: Fix %ds/%es clobber
  KVM: x86 emulator: convert bsf/bsr instructions to emulate_2op_SrcV_nobyte()
  KVM: VMX: unlike vmcs on fail path
  KVM: PPC: Emulator: clean up SPR reads and writes
  KVM: PPC: Emulator: clean up instruction parsing
  kvm/powerpc: Add new ioctl to retreive server MMU infos
  kvm/book3s: Make kernel emulated H_PUT_TCE available for "PR" KVM
  KVM: PPC: bookehv: Fix r8/r13 storing in level exception handler
  KVM: PPC: Book3S: Enable IRQs during exit handling
  KVM: PPC: Fix PR KVM on POWER7 bare metal
  KVM: PPC: Fix stbux emulation
  KVM: PPC: bookehv: Use lwz/stw instead of PPC_LL/PPC_STL for 32-bit fields
  ...
2012-05-24 16:17:30 -07:00
Srivatsa S. Bhat
4a70d2d990 smpboot, idle: Fix comment mismatch over idle_threads_init()
The comment over idle_threads_init() really talks about the functionality
of idle_init(). Move that comment to idle_init(), and add a suitable
comment over idle_threads_init().

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: suresh.b.siddha@intel.com
Cc: venki@google.com
Cc: nikunj@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20120524151100.2549.66501.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-24 22:58:08 +02:00
Srivatsa S. Bhat
ee74d13229 smpboot, idle: Optimize calls to smp_processor_id() in idle_threads_init()
While trying to initialize idle threads for all cpus, idle_threads_init()
calls smp_processor_id() in a loop, which is unnecessary. The intent
is to initialize idle threads for all non-boot cpus. So just use a variable
to note the boot cpu and use it in the loop.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: suresh.b.siddha@intel.com
Cc: venki@google.com
Cc: nikunj@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20120524151055.2549.64309.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-24 22:58:08 +02:00
Linus Torvalds
b343c8beec irqdomain changes for v3.5 merge window
Minor changes and fixups for irqdomain infrastructure.  Most
 important change adds ability to remove registered irqdomain.
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Merge tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux-2.6

Pull irqdomain changes from Grant Likely:
 "Minor changes and fixups for irqdomain infrastructure.  The most
  important change adds the ability to remove a registered irqdomain."

* tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux-2.6:
  irqdomain: Document size parameter of irq_domain_add_linear()
  irqdomain: trivial pr_fmt conversion.
  irqdomain: Kill off duplicate definitions.
  irqdomain: Make irq_domain_simple_map() static.
  irqdomain: Export remaining public API symbols.
  irqdomain: Support removal of IRQ domains.
2012-05-24 13:55:24 -07:00
Jiang Liu
818b0f3bfb genirq: Introduce irq_do_set_affinity() to reduce duplicated code
All invocations of chip->irq_set_affinity() are doing the same return
value checks. Let them all use a common function.

[ tglx: removed the silly likely while at it ]

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Keping Chen <chenkeping@huawei.com>
Link: http://lkml.kernel.org/r/1333120296-13563-3-git-send-email-jiang.liu@huawei.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-05-24 22:36:40 +02:00
Linus Torvalds
c7523a7c88 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner.

Various trivial conflict fixups in arch Kconfig due to addition of
unrelated entries nearby.  And one slightly more subtle one for sparc32
(new user of GENERIC_CLOCKEVENTS), fixed up as per Thomas.

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
  timekeeping: Fix a few minor newline issues.
  time: remove obsolete declaration
  ntp: Fix a stale comment and a few stray newlines.
  ntp: Correct TAI offset during leap second
  timers: Fixup the Kconfig consolidation fallout
  x86: Use generic time config
  unicore32: Use generic time config
  um: Use generic time config
  tile: Use generic time config
  sparc: Use: generic time config
  sh: Use generic time config
  score: Use generic time config
  s390: Use generic time config
  openrisc: Use generic time config
  powerpc: Use generic time config
  mn10300: Use generic time config
  mips: Use generic time config
  microblaze: Use generic time config
  m68k: Use generic time config
  m32r: Use generic time config
  ...
2012-05-24 13:29:46 -07:00