Add kernel-doc function headers in kernel/resource.c and use them in DocBook.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add kernel-doc function headers in kernel/dma.c and use it in DocBook.
Clean up kernel-doc in mca_dma.h (the colon (':') represents a
section header).
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some uses of kallsyms_lookup() do not need to find out the name of a symbol
and its module's name it belongs. This is specially true in arch specific
code, which needs to unwind the stack to show the back trace during oops
(mips is an example). In this specific case, we just need to retreive the
function's size and the offset of the active intruction inside it.
Adds a new entry "kallsyms_lookup_size_offset()" This new entry does
exactly the same as kallsyms_lookup() but does not require any buffers to
store any names.
It returns 0 if it fails otherwise 1.
Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Revert Andrew Morton's patch to temporarily hack around the lack of a
declaration of sigset_t in linux/compat.h to make the block-disablement
patches build on IA64. This got accidentally pushed to Linus and should
be fixed in a different manner.
Also make linux/compat.h #include asm/signal.h to gain a definition of
sigset_t so that it can externally declare sigset_from_compat().
This has been compile-tested for i386, x86_64, ia64, mips, mips64, frv, ppc and
ppc64 and run-tested on frv.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are a few places in the kernel where the init task is signaled. The
ctrl+alt+del sequence is one them. It kills a task, usually init, using a
cached pid (cad_pid).
This patch replaces the pid_t by a struct pid to avoid pid wrap around
problem. The struct pid is initialized at boot time in init() and can be
modified through systctl with
/proc/sys/kernel/cad_pid
[ I haven't found any distro using it ? ]
It also introduces a small helper routine kill_cad_pid() which is used
where it seemed ok to use cad_pid instead of pid 1.
[akpm@osdl.org: cleanups, build fix]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
proc_pid_make_inode:
ei->pid = get_pid(task_pid(task));
I think this is not safe. get_pid() can be preempted after checking "pid
!= NULL". Then the task exits, does detach_pid(), and RCU frees the pid.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The use of execve() in the kernel is dubious, since it relies on the
__KERNEL_SYSCALLS__ mechanism that stores the result in a global errno
variable. As a first step of getting rid of this, change all users to a
global kernel_execve function that returns a proper error code.
This function is a terrible hack, and a later patch removes it again after the
kernel syscalls are gone.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes copy_namespaces()'s error path.
when new nsproxy (new_ns) is created pointers to namespaces (ipc, uts) are
copied from the old nsproxy. Later in copy_utsname, copy_ipcs, etc.
according namespaces are get-ed. On error path needed namespaces are
put-ed, so there's no need to put new nsproxy itelf as it woud cause
putting namespaces for the second time.
Found when incorporating namespaces into OpenVZ kernel.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch set allows to unshare IPCs and have a private set of IPC objects
(sem, shm, msg) inside namespace. Basically, it is another building block of
containers functionality.
This patch implements core IPC namespace changes:
- ipc_namespace structure
- new config option CONFIG_IPC_NS
- adds CLONE_NEWIPC flag
- unshare support
[clg@fr.ibm.com: small fix for unshare of ipc namespace]
[akpm@osdl.org: build fix]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The nsproxy was being copied in unshare() when anything was being unshared,
even if it was something not referenced from nsproxy. This should end up
in some cases with far more memory usage than necessary.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement a CLONE_NEWUTS flag, and use it at clone and sys_unshare.
[clg@fr.ibm.com: IPC unshare fix]
[bunk@stusta.de: cleanup]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Sysctl uts patch. This will need to be done another way, but since sysctl
itself needs to be container aware, 'the right thing' is a separate patchset.
[akpm@osdl.org: ia64 build fix]
[sam.vilain@catalyst.net.nz: cleanup]
[sam.vilain@catalyst.net.nz: add proc_do_utsns_string]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch defines the uts namespace and some manipulators.
Adds the uts namespace to task_struct, and initializes a
system-wide init namespace.
It leaves a #define for system_utsname so sysctl will compile.
This define will be removed in a separate patch.
[akpm@osdl.org: build fix, cleanup]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In some places, particularly drivers and __init code, the init utsns is the
appropriate one to use. This patch replaces those with a the init_utsname
helper.
Changes: Removed several uses of init_utsname(). Hope I picked all the
right ones in net/ipv4/ipconfig.c. These are now changed to
utsname() (the per-process namespace utsname) in the previous
patch (2/7)
[akpm@osdl.org: CIFS fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace references to system_utsname to the per-process uts namespace
where appropriate. This includes things like uname.
Changes: Per Eric Biederman's comments, use the per-process uts namespace
for ELF_PLATFORM, sunrpc, and parts of net/ipv4/ipconfig.c
[jdike@addtoit.com: UML fix]
[clg@fr.ibm.com: cleanup]
[akpm@osdl.org: build fix]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
exit_task_namespaces() has replaced the former exit_namespace(). It
invalidates task->nsproxy and associated namespaces. This is an issue for
the (futur) pid namespace which is required to be valid in exit_notify().
This patch moves exit_task_namespaces() after exit_notify() to keep nsproxy
valid.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This moves the mount namespace into the nsproxy. The mount namespace count
now refers to the number of nsproxies point to it, rather than the number of
tasks. As a result, the unshare_namespace() function in kernel/fork.c no
longer checks whether it is being shared.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move the init_nsproxy definition out of arch/ into kernel/nsproxy.c. This
avoids all arches having to be updated. Compiles and boots on s390.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds a nsproxy structure to the task struct. Later patches will
move the fs namespace pointer into this structure, and introduce a new utsname
namespace into the nsproxy.
The vserver and openvz functionality, then, would be implemented in large part
by virtualizing/isolating more and more resources into namespaces, each
contained in the nsproxy.
[akpm@osdl.org: build fix]
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch makes the needlessly global _proc_do_string() static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The logic in proc_do_string is worth re-using without passing in a
ctl_table structure (say, we want to calculate a pointer and pass that in
instead); pass in the two fields it uses from that structure as explicit
arguments.
Signed-off-by: Sam Vilain <sam.vilain@catalyst.net.nz>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
cpumask: ensure that the cpu_online_map and cpu_possible_map bitmasks, and
hence all the macros in <linux/cpumask.h> that require them, are available to
modules for all supported combinations of architecture and CONFIG_SMP.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kprobe_flush_task() possibly calls kfree function during holding
kretprobe_lock spinlock, if kfree function is probed by kretprobe that will
incur spinlock deadlock. This patch moves kfree function out scope of
kretprobe_lock.
Signed-off-by: bibo, mao <bibo.mao@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When kprobe is re-entered, the re-entered kprobe kernel path will will call
atomic_notifier_call_chain function, if this function is kprobed that will
incur numerous kprobe recursive fault. This patch disallows kprobes on
atomic_notifier_call_chain function.
Signed-off-by: bibo, mao <bibo.mao@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Whitespace is used to indent, this patch cleans up these sentences by
kernel coding style.
Signed-off-by: bibo, mao <bibo.mao@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In an effort to make kprobe modules more portable, here is a patch that:
o Introduces the "symbol_name" field to struct kprobe.
The symbol->address resolution now happens in the kernel in an
architecture agnostic manner. 64-bit powerpc users no longer have
to specify the ".symbols"
o Introduces the "offset" field to struct kprobe to allow a user to
specify an offset into a symbol.
o The legacy mechanism of specifying the kprobe.addr is still supported.
However, if both the kprobe.addr and kprobe.symbol_name are specified,
probe registration fails with an -EINVAL.
o The symbol resolution code uses kallsyms_lookup_name(). So
CONFIG_KPROBES now depends on CONFIG_KALLSYMS
o Apparantly kprobe modules were the only legitimate out-of-tree user of
the kallsyms_lookup_name() EXPORT. Now that the symbol resolution
happens in-kernel, remove the EXPORT as suggested by Christoph Hellwig
o Modify tcp_probe.c that uses the kprobe interface so as to make it
work on multiple platforms (in its earlier form, the code wouldn't
work, say, on powerpc)
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The problem with remembering a user space process by its pid is that it is
possible that the process will exit, pid wrap around will occur.
Converting to a struct pid avoid that problem, and paves the way for
implementing a pid namespace.
Also since usb is the only user of kill_proc_info_as_uid rename
kill_proc_info_as_uid to kill_pid_info_as_uid and have the new version take
a struct pid.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This updates my proc: readdir race fix (take 3) patch
to account for the changes made by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
to introduce struct pspace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Define a per-container pid space object. And create one instance of this
object, init_pspace, to define the entire pid space. Subsequent patches
will provide/use interfaces to create/destroy pid spaces.
Its a subset/rework of Eric Biederman's patch
http://lkml.org/lkml/2006/2/6/285 .
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Andrey Savochkin <saw@sw.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move struct pidmap and PIDMAP_ENTRIES to a new file, include/linux/pspace.h
where it will be used in subsequent patches to define pid spaces.
Its a subset of Eric Biederman's patch http://lkml.org/lkml/2006/2/6/285
[akpm@osdl.org: cleanups]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use struct pidmap instead of pidmap_t.
This updates my proc: readdir race fix (take 3) patch
to account for the changes made by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
to kill pidmap_t.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use struct pidmap instead of pidmap_t.
Its a subset of Eric Biederman's patch http://lkml.org/lkml/2006/2/6/271.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
File handles can be requested to send sigio and sigurg to processes. By
tracking the destination processes using struct pid instead of pid_t we make
the interface safe from all potential pid wrap around problems.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
pids aren't something that drivers should care about. However there are a lot
of helper layers in the kernel that do care, and are built as modules. Before
I can convert them to using struct pid instead of pid_t I need to export the
appropriate symbols so they can continue to be built.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently the signal functions all either take a task or a pid_t argument.
This patch implements variants that take a struct pid *. After all of the
users have been update it is my intention to remove the variants that take a
pid_t as using pid_t can be more work (an extra hash table lookup) and
difficult to get right in the presence of multiple pid namespaces.
There are two kinds of functions introduced in this patch. The are the
general use functions kill_pgrp and kill_pid which take a priv argument that
is ultimately used to create the appropriate siginfo information, Then there
are _kill_pgrp_info, kill_pgrp_info, kill_pid_info the internal implementation
helpers that take an explicit siginfo.
The distinction is made because filling out an explcit siginfo is tricky, and
will be even more tricky when pid namespaces are introduced.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The problem: An opendir, readdir, closedir sequence can fail to report
process ids that are continually in use throughout the sequence of system
calls. For this race to trigger the process that proc_pid_readdir stops at
must exit before readdir is called again.
This can cause ps to fail to report processes, and it is in violation of
posix guarantees and normal application expectations with respect to
readdir.
Currently there is no way to work around this problem in user space short
of providing a gargantuan buffer to user space so the directory read all
happens in on system call.
This patch implements the normal directory semantics for proc, that
guarantee that a directory entry that is neither created nor destroyed
while reading the directory entry will be returned. For directory that are
either created or destroyed during the readdir you may or may not see them.
Furthermore you may seek to a directory offset you have previously seen.
These are the guarantee that ext[23] provides and that posix requires, and
more importantly that user space expects. Plus it is a simple semantic to
implement reliable service. It is just a matter of calling readdir a
second time if you are wondering if something new has show up.
These better semantics are implemented by scanning through the pids in
numerical order and by making the file offset a pid plus a fixed offset.
The pid scan happens on the pid bitmap, which when you look at it is
remarkably efficient for a brute force algorithm. Given that a typical
cache line is 64 bytes and thus covers space for 64*8 == 200 pids. There
are only 40 cache lines for the entire 32K pid space. A typical system
will have 100 pids or more so this is actually fewer cache lines we have to
look at to scan a linked list, and the worst case of having to scan the
entire pid bitmap is pretty reasonable.
If we need something more efficient we can go to a more efficient data
structure for indexing the pids, but for now what we have should be
sufficient.
In addition this takes no additional locks and is actually less code than
what we are doing now.
Also another very subtle bug in this area has been fixed. It is possible
to catch a task in the middle of de_thread where a thread is assuming the
thread of it's thread group leader. This patch carefully handles that case
so if we hit it we don't fail to return the pid, that is undergoing the
de_thread dance.
Thanks to KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> for
providing the first fix, pointing this out and working on it.
[oleg@tv-sign.ru: fix it]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When listing loaded modules during an oops or panic, also list each
module's Tainted flags if non-zero (P: Proprietary or F: Forced load only).
If a module is did not taint the kernel, it is just listed like
usbcore
but if it did taint the kernel, it is listed like
wizmodem(PF)
Example:
[ 3260.121718] Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP:
[ 3260.121729] [<ffffffff8804c099>] :dump_test:proc_dump_test+0x99/0xc8
[ 3260.121742] PGD fe8d067 PUD 264a6067 PMD 0
[ 3260.121748] Oops: 0002 [1] SMP
[ 3260.121753] CPU 1
[ 3260.121756] Modules linked in: dump_test(P) snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device ide_cd generic ohci1394 snd_hda_intel snd_hda_codec snd_pcm snd_timer snd ieee1394 snd_page_alloc piix ide_core arcmsr aic79xx scsi_transport_spi usblp
[ 3260.121785] Pid: 5556, comm: bash Tainted: P 2.6.18-git10 #1
[Alternatively, I can look into listing tainted flags with 'lsmod',
but that won't help in oopsen/panics so much.]
[akpm@osdl.org: cleanup]
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Using the infrastructure created in previous patches implement support to
pipe core dumps into programs.
This is done by overloading the existing core_pattern sysctl
with a new syntax:
|program
When the first character of the pattern is a '|' the kernel will instead
threat the rest of the pattern as a command to run. The core dump will be
written to the standard input of that program instead of to a file.
This is useful for having automatic core dump analysis without filling up
disks. The program can do some simple analysis and save only a summary of
the core dump.
The core dump proces will run with the privileges and in the name space of
the process that caused the core dump.
I also increased the core pattern size to 128 bytes so that longer command
lines fit.
Most of the changes comes from allowing core dumps without seeks. They are
fairly straight forward though.
One small incompatibility is that if someone had a core pattern previously
that started with '|' they will get suddenly new behaviour. I think that's
unlikely to be a real problem though.
Additional background:
> Very nice, do you happen to have a program that can accept this kind of
> input for crash dumps? I'm guessing that the embedded people will
> really want this functionality.
I had a cheesy demo/prototype. Basically it wrote the dump to a file again,
ran gdb on it to get a backtrace and wrote the summary to a shared directory.
Then there was a simple CGI script to generate a "top 10" crashes HTML
listing.
Unfortunately this still had the disadvantage to needing full disk space for a
dump except for deleting it afterwards (in fact it was worse because over the
pipe holes didn't work so if you have a holey address map it would require
more space).
Fortunately gdb seems to be happy to handle /proc/pid/fd/xxx input pipes as
cores (at least it worked with zsh's =(cat core) syntax), so it would be
likely possible to do it without temporary space with a simple wrapper that
calls it in the right way. I ran out of time before doing that though.
The demo prototype scripts weren't very good. If there is really interest I
can dig them out (they are currently on a laptop disk on the desk with the
laptop itself being in service), but I would recommend to rewrite them for any
serious application of this and fix the disk space problem.
Also to be really useful it should probably find a way to automatically fetch
the debuginfos (I cheated and just installed them in advance). If nobody else
does it I can probably do the rewrite myself again at some point.
My hope at some point was that desktops would support it in their builtin
crash reporters, but at least the KDE people I talked too seemed to be happy
with their user space only solution.
Alan sayeth:
I don't believe that piping as such as neccessarily the right model, but
the ability to intercept and processes core dumps from user space is asked
for by many enterprise users as well. They want to know about, capture,
analyse and process core dumps, often centrally and in automated form.
[akpm@osdl.org: loff_t != unsigned long]
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A new member in the ever growing family of call_usermode* functions is
born. The new call_usermodehelper_pipe() function allows to pipe data to
the stdin of the called user mode progam and behaves otherwise like the
normal call_usermodehelp() (except that it always waits for the child to
finish)
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is mostly included for parity with dec_nlink(), where we will have some
more hooks. This one should stay pretty darn straightforward for now.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ChangeLog:
Feedbacks from Andrew Morton:
- define TS_COMM_LEN to 32
- change acct_stimexpd field of task_struct to be of
cputime_t, which is to be used to save the tsk->stime
of last timer interrupt update.
- a new Documentation/accounting/taskstats-struct.txt
to describe fields of taskstats struct.
Feedback from Balbir Singh:
- keep the stime of a task to be zero when both stime
and utime are zero as recoreded in task_struct.
Misc:
- convert accumulated RSS/VM from platform dependent
pages-ticks to MBytes-usecs in the kernel
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There were a few accounting data/macros that are used in CSA but are #ifdef'ed
inside CONFIG_BSD_PROCESS_ACCT. This patch is to change those ifdef's from
CONFIG_BSD_PROCESS_ACCT to CONFIG_TASK_XACCT. A few defines are moved from
kernel/acct.c and include/linux/acct.h to kernel/tsacct.c and
include/linux/tsacct_kern.h.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add extended system accounting handling over taskstats interface. A
CONFIG_TASK_XACCT flag is created to enable the extended accounting code.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add some basic accounting fields to the taskstats struct, add a new
kernel/tsacct.c to handle basic accounting data handling upon exit. A handle
is added to taskstats.c to invoke the basic accounting data handling.
Signed-off-by: Jay Lan <jlan@sgi.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Chris Sturtivant <csturtiv@sgi.com>
Cc: Tony Ernst <tee@sgi.com>
Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net>
Cc: "Michal Piotrowski" <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The addition of the CSA patch pushed the size of struct taskstats to 256
bytes. This exposed a problem with prepare_reply(), we were not allocating
space for the netlink and genetlink header. It worked earlier because
alloc_skb() would align the skb to SMP_CACHE_BYTES, which added some additonal
bytes.
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jamal Hadi <hadi@cyberus.ca>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies.
So we can kill wall_jiffies completely.
This is just a cleanup and logically should not change any real behavior
except for one thing: RTC updating code in (old) ppc and xtensa use a
condition "jiffies - wall_jiffies == 1". This condition is never met so I
suppose it is just a bug. I just remove that condition only instead of
kill the whole "if" block.
[heiko.carstens@de.ibm.com: s390 build fix and cleanup]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch contains the following possible cleanups:
- make the following needlessly global function static:
- ntp_update_frequency()
- make the following needlessly global variables static:
- time_state
- time_offset
- time_constant
- time_reftime
- remove the following read-only global variable:
- time_precision
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This converts the kernel ntp model into a model which matches the nanokernel
reference implementations. The previous patches already increased the
resolution and precision of the computations, so that this conversion becomes
quite simple.
<linux@horizon.com> explains:
The original NTP kernel interface was defined in units of microseconds.
That's what Linux implements. As computers have gotten faster and can now
split microseconds easily, a new kernel interface using nanosecond units was
defined ("the nanokernel", confusing as that name is to OS hackers), and
there's an STA_NANO bit in the adjtimex() status field to tell the application
which units it's using.
The current ntpd supports both, but Linux loses some possible timing
resolution because of quantization effects, and the ntpd hackers would really
like to be able to drop the backwards compatibility code.
Ulrich Windl has been maintaining a patch set to do the conversion for years,
but it's hard to keep in sync.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This converts time_freq to a scaled nsec value and adds around 6bit of extra
resolution. This pushes the time_freq to its 32bit limits so the calculatons
have to be done with 64bit.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
time_tolerance isn't changed at all in the kernel, so simply remove it, this
simplifies the next patch, as it avoids a number of conversions.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This folds update_ntp_one_tick() into second_overflow() and adds time_adjust
to the tick length, this makes time_next_adjust unnecessary. This slightly
changes the adjtime() behaviour, instead of applying it to the next tick, it's
applied to the next second.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This converts time_offset into a scaled per tick value. This avoids now
completely the crude compensation in second_overflow().
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds the frequency part to ntp_update_frequency().
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This makes time_adj local to second_overflow() and integrates it into the tick
length instead of adding it everytime.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This introduces ntp_update_frequency() and deinlines ntp_clear() (as it's not
performance critical). ntp_update_frequency() calculates the base tick length
using tick_usec and adds a base adjustment, in case the frequency doesn't
divide evenly by HZ.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move all the NTP related code to ntp.c
[akpm@osdl.org: cleanups, build fix]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
On systems running with virtual cpus there is optimization potential in
regard to spinlocks and rw-locks. If the virtual cpu that has taken a lock
is known to a cpu that wants to acquire the same lock it is beneficial to
yield the timeslice of the virtual cpu in favour of the cpu that has the
lock (directed yield).
With CONFIG_PREEMPT="n" this can be implemented by the architecture without
common code changes. Powerpc already does this.
With CONFIG_PREEMPT="y" the lock loops are coded with _raw_spin_trylock,
_raw_read_trylock and _raw_write_trylock in kernel/spinlock.c. If the lock
could not be taken cpu_relax is called. A directed yield is not possible
because cpu_relax doesn't know anything about the lock. To be able to
yield the lock in favour of the current lock holder variants of cpu_relax
for spinlocks and rw-locks are needed. The new _raw_spin_relax,
_raw_read_relax and _raw_write_relax primitives differ from cpu_relax
insofar that they have an argument: a pointer to the lock structure.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix up kernel/sys.c to be consistent with CodingStyle and the rest of the
file.
Signed-off-by: Cal Peake <cp@absolutedigital.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add infrastructure to track "maximum allowable latency" for power saving
policies.
The reason for adding this infrastructure is that power management in the
idle loop needs to make a tradeoff between latency and power savings
(deeper power save modes have a longer latency to running code again). The
code that today makes this tradeoff just does a rather simple algorithm;
however this is not good enough: There are devices and use cases where a
lower latency is required than that the higher power saving states provide.
An example would be audio playback, but another example is the ipw2100
wireless driver that right now has a very direct and ugly acpi hook to
disable some higher power states randomly when it gets certain types of
error.
The proposed solution is to have an interface where drivers can
* announce the maximum latency (in microseconds) that they can deal with
* modify this latency
* give up their constraint
and a function where the code that decides on power saving strategy can
query the current global desired maximum.
This patch has a user of each side: on the consumer side, ACPI is patched
to use this, on the producer side the ipw2100 driver is patched.
A generic maximum latency is also registered of 2 timer ticks (more and you
lose accurate time tracking after all).
While the existing users of the patch are x86 specific, the infrastructure
is not. I'd like to ask the arch maintainers of other architectures if the
infrastructure is generic enough for their use (assuming the architecture
has such a tradeoff as concept at all), and the sound/multimedia driver
owners to look at the driver facing API to see if this is something they
can use.
[akpm@osdl.org: cleanups]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Create a new header file, fs/internal.h, for common definitions local to the
sources in the fs/ directory.
Move extern definitions that should be in header files from fs/*.c to
fs/internal.h or other main header files where they span directories.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove the duplicate declaration of exit_io_context() from linux/sched.h.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix obscure race condition in kernel/cpuset.c attach_task() code.
There is basically zero chance of anyone accidentally being harmed by this
race.
It requires a special 'micro-stress' load and a special timing loop hacks
in the kernel to hit in less than an hour, and even then you'd have to hit
it hundreds or thousands of times, followed by some unusual and senseless
cpuset configuration requests, including removing the top cpuset, to cause
any visibly harm affects.
One could, with perhaps a few days or weeks of such effort, get the
reference count on the top cpuset below zero, and manage to crash the
kernel by asking to remove the top cpuset.
I found it by code inspection.
The race was introduced when 'the_top_cpuset_hack' was introduced, and one
piece of code was not updated. An old check for a possibly null task
cpuset pointer needed to be changed to a check for a task marked
PF_EXITING. The pointer can't be null anymore, thanks to
the_top_cpuset_hack (documented in kernel/cpuset.c). But the task could
have gone into PF_EXITING state after it was found in the task_list scan.
If a task is PF_EXITING in this code, it is possible that its task->cpuset
pointer is pointing to the top cpuset due to the_top_cpuset_hack, rather
than because the top_cpuset was that tasks last valid cpuset. In that
case, the wrong cpuset reference counter would be decremented.
The fix is trivial. Instead of failing the system call if the tasks cpuset
pointer is null here, fail it if the task is in PF_EXITING state.
The code for 'the_top_cpuset_hack' that changes an exiting tasks cpuset to
the top_cpuset is done without locking, so could happen at anytime. But it
is done during the exit handling, after the PF_EXITING flag is set. So if
we verify that a task is still not PF_EXITING after we copy out its cpuset
pointer (into 'oldcs', below), we know that 'oldcs' is not one of these
hack references to the top_cpuset.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With CONFIG_DEBUG_LOCK_ALLOC turned off i was getting sporadic failures in
the locking self-test:
------------>
| Locking API testsuite:
----------------------------------------------------------------------------
| spin |wlock |rlock |mutex | wsem | rsem |
--------------------------------------------------------------------------
A-A deadlock: ok | ok | ok | ok | ok | ok |
A-B-B-A deadlock: ok | ok | ok | ok | ok | ok |
A-B-B-C-C-A deadlock: ok | ok | ok | ok | ok | ok |
A-B-C-A-B-C deadlock: ok | ok | ok | ok | ok | ok |
A-B-B-C-C-D-D-A deadlock: ok |FAILED| ok | ok | ok | ok |
A-B-C-D-B-D-D-A deadlock: ok | ok | ok | ok | ok | ok |
A-B-C-D-B-C-D-A deadlock: ok | ok | ok | ok | ok |FAILED|
after much debugging it turned out to be caused by accidental chain-hash
key collisions. The current hash is:
#define iterate_chain_key(key1, key2) \
(((key1) << MAX_LOCKDEP_KEYS_BITS/2) ^ \
((key1) >> (64-MAX_LOCKDEP_KEYS_BITS/2)) ^ \
(key2))
where MAX_LOCKDEP_KEYS_BITS is 11. This hash is pretty good as it will
shift by 5 bits in every iteration, where every new ID 'mixed' into the
hash would have up to 11 bits. But because there was a 6 bits overlap
between subsequent IDs and their high bits tended to be similar, there was
a chance for accidental chain-hash collision for a low number of locks
held.
the solution is to shift by 11 bits:
#define iterate_chain_key(key1, key2) \
(((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
(key2))
This keeps the hash perfect up to 5 locks held, but even above that the
hash is still good because 11 bits is a relative prime to the total 64
bits, so a complete match will only occur after 64 held locks (which doesnt
happen in Linux). Even after 5 locks held, entropy of the 5 IDs mixed into
the hash is already good enough so that overlap doesnt generate a colliding
hash ID.
with this change the false positives went away.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add tty locking around the audit and accounting code.
The whole current->signal-> locking is all deeply strange but it's for
someone else to sort out. Add rather than replace the lock for acct.c
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I had to look back: this code was extracted from the module.c code in 2005.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I've been using systemtap for some debugging and I noticed that it can't
probe a lot of modules. Turns out it's kind of silly, the sections section
of /sys/module is limited to 32byte filenames and many of the actual
sections are a a bit longer than that.
[akpm@osdl.org: rewrite to use dymanic allocation]
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The cpuset code handling hot unplug of CPUs or Memory Nodes was incorrect -
it could remove a CPU or Node from the top cpuset, while leaving it still
in some child cpusets.
One basic rule of cpusets is that each cpusets cpus and mems are subsets of
its parents. The cpuset hot unplug code violated this rule.
So the cpuset hotunplug handler must walk down the tree, removing any
removed CPU or Node from all cpusets.
However, it is not allowed to make a cpusets cpus or mems become empty.
They can only transition from empty to non-empty, not back.
So if the last CPU or Node would be removed from a cpuset by the above
walk, we scan back up the cpuset hierarchy, finding the nearest ancestor
that still has something online, and copy its CPU or Memory placement.
Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: Nathan Lynch <ntl@pobox.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the list of memory nodes allowed to tasks in the top (root) nodeset
to dynamically track what cpus are online, using a call to a cpuset hook
from the memory hotplug code. Make this top cpus file read-only.
On systems that have cpusets configured in their kernel, but that aren't
actively using cpusets (for some distros, this covers the majority of
systems) all tasks end up in the top cpuset.
If that system does support memory hotplug, then these tasks cannot make
use of memory nodes that are added after system boot, because the memory
nodes are not allowed in the top cpuset. This is a surprising regression
over earlier kernels that didn't have cpusets enabled.
One key motivation for this change is to remain consistent with the
behaviour for the top_cpuset's 'cpus', which is also read-only, and which
automatically tracks the cpu_online_map.
This change also has the minor benefit that it fixes a long standing,
little noticed, minor bug in cpusets. The cpuset performance tweak to
short circuit the cpuset_zone_allowed() check on systems with just a single
cpuset (see 'number_of_cpusets', in linux/cpuset.h) meant that simply
changing the 'mems' of the top_cpuset had no affect, even though the change
(the write system call) appeared to succeed. With the following change,
that write to the 'mems' file fails -EACCES, and the 'mems' file stubbornly
refuses to be changed via user space writes. Thus no one should be mislead
into thinking they've changed the top_cpusets's 'mems' when in affect they
haven't.
In order to keep the behaviour of cpusets consistent between systems
actively making use of them and systems not using them, this patch changes
the behaviour of the 'mems' file in the top (root) cpuset, making it read
only, and making it automatically track the value of node_online_map. Thus
tasks in the top cpuset will have automatic use of hot plugged memory nodes
allowed by their cpuset.
[akpm@osdl.org: build fix]
[bunk@stusta.de: build fix]
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I am not sure about this patch, I am asking Ingo to take a decision.
task_struct->state == EXIT_DEAD is a very special case, to avoid a confusion
it makes sense to introduce a new state, TASK_DEAD, while EXIT_DEAD should
live only in ->exit_state as documented in sched.h.
Note that this state is not visible to user-space, get_task_state() masks off
unsuitable states.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
schedule() checks PF_DEAD on every context switch and sets ->state = EXIT_DEAD
to ensure that the exiting task will be deactivated. Note that this EXIT_DEAD
is in fact a "random" value, we can use any bit except normal TASK_XXX values.
It is better to set this state in do_exit() along with PF_DEAD flag and remove
that check in schedule().
We are safe wrt concurrent try_to_wake_up() (for example ptrace, tkill), it
can not change task's ->state: the 'state' argument of try_to_wake_up() can't
have EXIT_DEAD bit. And in case when try_to_wake_up() sees a stale value of
->state == TASK_RUNNING it will do nothing.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is ok to do find_task_by_pid() + get_task_struct() under
rcu_read_lock(), we cand drop tasklist_lock.
Note that testing of ->exit_state is racy with or without tasklist anyway.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
copy_process:
// holds tasklist_lock + ->siglock
/*
* inherit ioprio
*/
p->ioprio = current->ioprio;
Why? ->ioprio was already copied in dup_task_struct(). I guess this is
needed to ensure that the child can't escape
sys_ioprio_set(IOPRIO_WHO_{PGRP,USER}), yes?
In that case we don't need ->siglock held, and the comment should be
updated.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I am not sure this patch is correct: I can't understand what the current
code does, and I don't know what it was supposed to do.
The comment says:
* can't change policy, except between SCHED_NORMAL
* and SCHED_BATCH:
The code:
if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) &&
(policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) &&
But this is equivalent to:
if ( (is_rt_policy(policy) && has_rt_policy(p)) &&
which means something different. We can't _decrease_ the current
->rt_priority with such a check (if rlim[RLIMIT_RTPRIO] == 0).
Probably, it was supposed to be:
if ( !(policy == SCHED_NORMAL && p->policy == SCHED_BATCH) &&
!(policy == SCHED_BATCH && p->policy == SCHED_NORMAL)
this matches the comment, but strange: it doesn't allow to _drop_ the
realtime priority when rlim[RLIMIT_RTPRIO] == 0.
I think the right check would be:
/* can't set/change rt policy */
if (is_rt_policy(policy) &&
policy != p->policy &&
!rlim_rtprio)
return -EPERM;
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Imho, makes the code a bit easier to read.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Get rid of an extraneous printk in kernel_restart().
Signed-off-by: Cal Peake <cp@absolutedigital.net>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If ____call_usermodehelper fails, we're not interested in the child
process' exit value, but the real error, so let's stop wait_for_helper from
overwriting it in that case.
Issue discovered by Benedikt Böhm while working on a Linux-VServer usermode
helper.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If we are going to BUG() not panic() here then we should cover the case of
the BUG being compiled out
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes a couple of compiler warnings, and adds paranoia checks as well.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390
timer interrupt handler with this change.
Currently update_times() calculates ticks by "jiffies - wall_jiffies", but
callers of do_timer() should know how many ticks to update. Passing ticks
get rid of this redundant calculation. Also there are another redundancy
pointed out by Martin Schwidefsky.
This cleanup make a barrier added by
5aee405c66 needless. So this patch removes
it.
As a bonus, this cleanup make wall_jiffies can be removed easily, since now
wall_jiffies is always synced with jiffies. (This patch does not really
remove wall_jiffies. It would be another cleanup patch)
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This tightens up __dequeue_signal a little. It also avoids doing
recalc_sigpending twice in a row, instead doing it once in dequeue_signal.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This check has been obsolete since the introduction of TASK_TRACED. Now
TASK_STOPPED always means job control stop.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a posix_cpu_nsleep() sleep is interrupted by a signal more than twice, it
incorrectly reports the sleep time remaining to the user. Because
posix_cpu_nsleep() doesn't report back to the user when it's called from
restart function due to the wrong flags handling.
This patch, which applies after previous one, moves the nanosleep() function
from posix_cpu_nsleep() to do_cpu_nanosleep() and cleans up the flags handling
appropriately.
Signed-off-by: Toyo Abe <toyoa@mvista.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The clock_nanosleep() function does not return the time remaining when the
sleep is interrupted by a signal.
This patch creates a new call out, compat_clock_nanosleep_restart(), which
handles returning the remaining time after a sleep is interrupted. This
patch revives clock_nanosleep_restart(). It is now accessed via the new
call out. The compat_clock_nanosleep_restart() is used for compatibility
access.
Since this is implemented in compatibility mode the normal path is
virtually unaffected - no real performance impact.
Signed-off-by: Toyo Abe <toyoa@mvista.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Spawing ksoftirqd, migration, or watchdog, and calling init_timers_cpu()
may fail with small memory. If it happens in initcalls, kernel NULL
pointer dereference happens later. This patch makes crash happen
immediately in such cases. It seems a bit better than getting kernel NULL
pointer dereference later.
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Both __kfifo_put() and __kfifo_get() have header comments stating that if
there is but one concurrent reader and one concurrent writer, locking is not
necessary. This is almost the case, but a couple of memory barriers are
needed. Another option would be to change the header comments to remove the
bit about locking not being needed, and to change the those callers who
currently don't use locking to add the required locking. The attachment
analyzes this approach, but the patch below seems simpler.
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Cc: Stelian Pop <stelian@popies.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Lets do the same thing we do for oopses - print out the version in the
report. It's an extra line of output though. We could tack it on the end
of the INFO: lines, but that screws up Ingo's pretty output.
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().
Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.
Eric's original description:
There are a lot of places in the kernel where we test for init
because we give it special properties. Most significantly init
must not die. This results in code all over the kernel test
->pid == 1.
Introduce is_init to capture this case.
With multiple pid spaces for all of the cases affected we are
looking for only the first process on the system, not some other
process that has pid == 1.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fixed race on put_files_struct on exec with proc. Restoring files on
current on error path may lead to proc having a pointer to already kfree-d
files_struct.
->files changing at exit.c and khtread.c are safe as exit_files() makes all
things under lock.
Found during OpenVZ stress testing.
[akpm@osdl.org: add export]
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix "variable defined but not used" compiler warning in unwind.c when
CONFIG_MODULES is not set.
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some of the kerneldoc comments in this file are ignored since the lead-in
is malformed, using either "/*" or "/***" instead of "/**".
[rdunlap@xenotime.net: kerneldoc fixes]
Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Oleg brought up some interesting points about grabbing the pi_lock for some
protections. In this discussion, I realized that there are some places
that the pi_lock is being grabbed when it really wasn't necessary. Also
this patch does a little bit of clean up.
This patch basically does three things:
1) renames the "boost" variable to "chain_walk". Since it is used in
the debugging case when it isn't going to be boosted. It better
describes what the test is going to do if it succeeds.
2) moves get_task_struct to just before the unlocking of the wait_lock.
This removes duplicate code, and makes it a little easier to read. The
owner wont go away while either the pi_lock or the wait_lock are held.
3) removes the pi_locking and owner blocked checking completely from the
debugging case. This is because the grabbing the lock and doing the
check, then releasing the lock is just so full of races. It's just as
good to go ahead and call the pi_chain_walk function, since after
releasing the lock the owner can then block anyway, and we would have
missed that. For the debug case, we really do want to do the chain walk
to test for deadlocks anyway.
[oleg@tv-sign.ru: more of the same]
Signed-of-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Esben Nielsen <nielsen.esben@googlemail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
