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Commit Graph

94 Commits

Author SHA1 Message Date
Thomas Gleixner
87dc64480f posix-cpu-timers: Restructure expiry array
Now that the abused struct task_cputime is gone, it's more natural to
bundle the expiry cache and the list head of each clock into a struct and
have an array of those structs.

Follow the hrtimer naming convention of 'bases' and rename the expiry cache
to 'nextevt' and adapt all usage sites.

Generates also better code .text size shrinks by 80 bytes.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908262021140.1939@nanos.tec.linutronix.de
2019-08-28 11:50:39 +02:00
Thomas Gleixner
46b883995c posix-cpu-timers: Remove cputime_expires
The last users of the magic struct cputime based expiry cache are
gone. Remove the leftovers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.790209622@linutronix.de
2019-08-28 11:50:38 +02:00
Thomas Gleixner
001f797143 posix-cpu-timers: Make expiry checks array based
The expiry cache is an array indexed by clock ids. The new sample functions
allow to retrieve a corresponding array of samples.

Convert the fastpath expiry checks to make use of the new sample functions
and do the comparisons on the sample and the expiry array.

Make the check for the expiry array being zero array based as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.695481430@linutronix.de
2019-08-28 11:50:38 +02:00
Thomas Gleixner
b0d524f779 posix-cpu-timers: Provide array based sample functions
Instead of using task_cputime and doing the addition of utime and stime at
all call sites, it's way simpler to have a sample array which allows
indexed based checks against the expiry cache array.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.590362974@linutronix.de
2019-08-28 11:50:38 +02:00
Thomas Gleixner
c02b078e63 posix-cpu-timers: Switch check_*_timers() to array cache
Use the array based expiry cache in check_thread_timers() and convert the
store in check_process_timers() for consistency.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.408222378@linutronix.de
2019-08-28 11:50:36 +02:00
Thomas Gleixner
1b0dd96d0f posix-cpu-timers: Simplify set_process_cpu_timer()
The expiry cache can now be accessed as an array. Replace the per clock
checks with a simple comparison of the clock indexed array member.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.303316423@linutronix.de
2019-08-28 11:50:36 +02:00
Thomas Gleixner
3b495b22d0 posix-cpu-timers: Simplify timer queueing
Now that the expiry cache can be accessed as an array, the per clock
checking can be reduced to just comparing the corresponding array elements.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.212129449@linutronix.de
2019-08-28 11:50:36 +02:00
Thomas Gleixner
11b8462f7e posix-cpu-timers: Provide array based access to expiry cache
Using struct task_cputime for the expiry cache is a pretty odd choice and
comes with magic defines to rename the fields for usage in the expiry
cache.

struct task_cputime is basically a u64 array with 3 members, but it has
distinct members.

The expiry cache content is different than the content of task_cputime
because

  expiry[PROF]  = task_cputime.stime + task_cputime.utime
  expiry[VIRT]  = task_cputime.utime
  expiry[SCHED] = task_cputime.sum_exec_runtime

So there is no direct mapping between task_cputime and the expiry cache and
the #define based remapping is just a horrible hack.

Having the expiry cache array based allows further simplification of the
expiry code.

To avoid an all in one cleanup which is hard to review add a temporary
anonymous union into struct task_cputime which allows array based access to
it. That requires to reorder the members. Add a build time sanity check to
validate that the members are at the same place.

The union and the build time checks will be removed after conversion.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.105793824@linutronix.de
2019-08-28 11:50:35 +02:00
Thomas Gleixner
3a245c0f11 posix-cpu-timers: Move expiry cache into struct posix_cputimers
The expiry cache belongs into the posix_cputimers container where the other
cpu timers information is.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.014444012@linutronix.de
2019-08-28 11:50:35 +02:00
Thomas Gleixner
2b69942f90 posix-cpu-timers: Create a container struct
Per task/process data of posix CPU timers is all over the place which
makes the code hard to follow and requires ifdeffery.

Create a container to hold all this information in one place, so data is
consolidated and the ifdeffery can be confined to the posix timer header
file and removed from places like fork.

As a first step, move the cpu_timers list head array into the new struct
and clean up the initializers and simplify fork. The remaining #ifdef in
fork will be removed later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.819418976@linutronix.de
2019-08-28 11:50:33 +02:00
Thomas Gleixner
ab693c5a5e posix-cpu-timers: Move prof/virt_ticks into caller
The functions have only one caller left. No point in having them.

Move the almost duplicated code into the caller and simplify it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.729298382@linutronix.de
2019-08-28 11:50:33 +02:00
Thomas Gleixner
0476ff2c15 posix-cpu-timers: Sample task times once in expiry check
Sampling the task times twice does not make sense. Do it once.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.639878168@linutronix.de
2019-08-28 11:50:32 +02:00
Thomas Gleixner
8c2d74f037 posix-cpu-timers: Get rid of pointer indirection
Now that the sample functions have no return value anymore, the result can
simply be returned instead of using pointer indirection.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.535079278@linutronix.de
2019-08-28 11:50:32 +02:00
Thomas Gleixner
2092c1d4fe posix-cpu-timers: Simplify sample functions
All callers hand in a valdiated clock id. Remove the return value which was
unchecked in most places anyway.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.430475832@linutronix.de
2019-08-28 11:50:31 +02:00
Thomas Gleixner
5405d0051f posix-cpu-timers: Remove pointless return value check
set_process_cpu_timer() checks already whether the clock id is valid. No
point in checking the return value of the sample function. That allows to
simplify the sample function later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.339725769@linutronix.de
2019-08-28 11:50:30 +02:00
Thomas Gleixner
da020ce406 posix-cpu-timers: Use clock ID in posix_cpu_timer_rearm()
Extract the clock ID (PROF/VIRT/SCHED) from the clock selector and use it
as argument to the sample functions. That allows to simplify them once all
callers are fixed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.245357769@linutronix.de
2019-08-28 11:50:29 +02:00
Thomas Gleixner
99093c5b81 posix-cpu-timers: Use clock ID in posix_cpu_timer_get()
Extract the clock ID (PROF/VIRT/SCHED) from the clock selector and use it
as argument to the sample functions. That allows to simplify them once all
callers are fixed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.155487201@linutronix.de
2019-08-28 11:50:29 +02:00
Thomas Gleixner
c7a37c6f4c posix-cpu-timers: Use clock ID in posix_cpu_timer_set()
Extract the clock ID (PROF/VIRT/SCHED) from the clock selector and use it
as argument to the sample functions. That allows to simplify them once all
callers are fixed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.050770464@linutronix.de
2019-08-28 11:50:28 +02:00
Thomas Gleixner
24ab7f5a7b posix-cpu-timers: Consolidate thread group sample code
cpu_clock_sample_group() and cpu_timer_sample_group() are almost the
same. Before the rename one called thread_group_cputimer() and the other
thread_group_cputime(). Really intuitive function names.

Consolidate the functions and also avoid the thread traversal when
the thread group's accounting is already active.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.960966884@linutronix.de
2019-08-28 11:50:28 +02:00
Thomas Gleixner
c506bef424 posix-cpu-timers: Rename thread_group_cputimer() and make it static
thread_group_cputimer() is a complete misnomer. The function does two things:

 - For arming process wide timers it makes sure that the atomic time
   storage is up to date. If no cpu timer is armed yet, then the atomic
   time storage is not updated by the scheduler for performance reasons.

   In that case a full summing up of all threads needs to be done and the
   update needs to be enabled.

- Samples the current time into the caller supplied storage.

Rename it to thread_group_start_cputime(), make it static and fixup the
callsite.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.869350319@linutronix.de
2019-08-28 11:50:27 +02:00
Thomas Gleixner
a324956fae posix-cpu-timers: Sample directly in timer check
The thread group accounting is active, otherwise the expiry function would
not be running. Sample the thread group time directly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.780348088@linutronix.de
2019-08-28 11:50:27 +02:00
Thomas Gleixner
19298fbf45 posix-cpu-timers: Provide quick sample function for itimer
get_itimer() needs a sample of the current thread group cputime. It invokes
thread_group_cputimer() - which is a misnomer. That function also starts
eventually the group cputime accouting which is bogus because the
accounting is already active when a timer is armed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.599658199@linutronix.de
2019-08-28 11:50:26 +02:00
Thomas Gleixner
e5a8b65b4c posix-cpu-timers: Use common permission check in posix_cpu_timer_create()
Yet another copy of the same thing gone...

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.505833418@linutronix.de
2019-08-28 11:50:25 +02:00
Thomas Gleixner
bfcf3e92c6 posix-cpu-timers: Use common permission check in posix_cpu_clock_get()
Replace the next slightly different copy of permission checks. That also
removes the necessarity to check the return value of the sample functions
because the clock id is already validated.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192919.414813172@linutronix.de
2019-08-28 11:50:25 +02:00
Thomas Gleixner
6ae40e3fdc posix-cpu-timers: Provide task validation functions
The code contains three slightly different copies of validating whether a
given clock resolves to a valid task and whether the current caller has
permissions to access it.

Create central functions. Replace check_clock() as a first step and rename
it to something sensible.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190821192919.326097175@linutronix.de
2019-08-28 11:50:24 +02:00
Thomas Gleixner
dce3e8fd03 posix-cpu-timers: Remove tsk argument from run_posix_cpu_timers()
It's always current. Don't give people wrong ideas.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.945469967@linutronix.de
2019-08-21 20:27:16 +02:00
Thomas Gleixner
692117c1f7 posix-cpu-timers: Sanitize bogus WARNONS
Warning when p == NULL and then proceeding and dereferencing p does not
make any sense as the kernel will crash with a NULL pointer dereference
right away.

Bailing out when p == NULL and returning an error code does not cure the
underlying problem which caused p to be NULL. Though it might allow to
do proper debugging.

Same applies to the clock id check in set_process_cpu_timer().

Clean them up and make them return without trying to do further damage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.846497772@linutronix.de
2019-08-21 20:27:15 +02:00
Thomas Gleixner
7cb9a94c15 posix-cpu-timers: Fixup stale comment
The comment above cleanup_timers() is outdated. The timers are only removed
from the task/process list heads but not modified in any other way.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.747233612@linutronix.de
2019-08-20 22:09:53 +02:00
Thomas Gleixner
16118794ed posix-cpu-timers: Remove private interval storage
Posix CPU timers store the interval in private storage for historical
reasons (it_interval used to be a non scalar representation on 32bit
systems). This is gone and there is no reason for duplicated storage
anymore.

Use it_interval everywhere.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Link: https://lkml.kernel.org/r/20190111133500.945255655@linutronix.de
2019-01-15 16:36:13 +01:00
Thomas Gleixner
93ad0fc088 posix-cpu-timers: Unbreak timer rearming
The recent commit which prevented a division by 0 issue in the alarm timer
code broke posix CPU timers as an unwanted side effect.

The reason is that the common rearm code checks for timer->it_interval
being 0 now. What went unnoticed is that the posix cpu timer setup does not
initialize timer->it_interval as it stores the interval in CPU timer
specific storage. The reason for the separate storage is historical as the
posix CPU timers always had a 64bit nanoseconds representation internally
while timer->it_interval is type ktime_t which used to be a modified
timespec representation on 32bit machines.

Instead of reverting the offending commit and fixing the alarmtimer issue
in the alarmtimer code, store the interval in timer->it_interval at CPU
timer setup time so the common code check works. This also repairs the
existing inconistency of the posix CPU timer code which kept a single shot
timer armed despite of the interval being 0.

The separate storage can be removed in mainline, but that needs to be a
separate commit as the current one has to be backported to stable kernels.

Fixes: 0e334db6bb ("posix-timers: Fix division by zero bug")
Reported-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190111133500.840117406@linutronix.de
2019-01-15 16:34:37 +01:00
Juri Lelli
e6a2d72c10 posix-cpu-timers: Remove useless call to check_dl_overrun()
check_dl_overrun() is used to send a SIGXCPU to users that asked to be
informed when a SCHED_DEADLINE runtime overruns occur.

The function is called by check_thread_timers() already, so the call in
check_process_timers() is redundant/wrong (even though harmless).

Remove it.

Fixes: 34be39305a ("sched/deadline: Implement "runtime overrun signal" support")
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: linux-rt-users@vger.kernel.org
Cc: mtk.manpages@gmail.com
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Claudio Scordino <claudio@evidence.eu.com>
Link: https://lkml.kernel.org/r/20181107111032.32291-1-juri.lelli@redhat.com
2018-11-08 07:43:35 +01:00
Linus Torvalds
0214f46b3a Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman:
 "It was observed that a periodic timer in combination with a
  sufficiently expensive fork could prevent fork from every completing.
  This contains the changes to remove the need for that restart.

  This set of changes is split into several parts:

   - The first part makes PIDTYPE_TGID a proper pid type instead
     something only for very special cases. The part starts using
     PIDTYPE_TGID enough so that in __send_signal where signals are
     actually delivered we know if the signal is being sent to a a group
     of processes or just a single process.

   - With that prep work out of the way the logic in fork is modified so
     that fork logically makes signals received while it is running
     appear to be received after the fork completes"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
  signal: Don't send signals to tasks that don't exist
  signal: Don't restart fork when signals come in.
  fork: Have new threads join on-going signal group stops
  fork: Skip setting TIF_SIGPENDING in ptrace_init_task
  signal: Add calculate_sigpending()
  fork: Unconditionally exit if a fatal signal is pending
  fork: Move and describe why the code examines PIDNS_ADDING
  signal: Push pid type down into complete_signal.
  signal: Push pid type down into __send_signal
  signal: Push pid type down into send_signal
  signal: Pass pid type into do_send_sig_info
  signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
  signal: Pass pid type into group_send_sig_info
  signal: Pass pid and pid type into send_sigqueue
  posix-timers: Noralize good_sigevent
  signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
  pid: Implement PIDTYPE_TGID
  pids: Move the pgrp and session pid pointers from task_struct to signal_struct
  kvm: Don't open code task_pid in kvm_vcpu_ioctl
  pids: Compute task_tgid using signal->leader_pid
  ...
2018-08-21 13:47:29 -07:00
Eric W. Biederman
6883f81aac pid: Implement PIDTYPE_TGID
Everywhere except in the pid array we distinguish between a tasks pid and
a tasks tgid (thread group id).  Even in the enumeration we want that
distinction sometimes so we have added __PIDTYPE_TGID.  With leader_pid
we almost have an implementation of PIDTYPE_TGID in struct signal_struct.

Add PIDTYPE_TGID as a first class member of the pid_type enumeration and
into the pids array.  Then remove the __PIDTYPE_TGID special case and the
leader_pid in signal_struct.

The net size increase is just an extra pointer added to struct pid and
an extra pair of pointers of an hlist_node added to task_struct.

The effect on code maintenance is the removal of a number of special
cases today and the potential to remove many more special cases as
PIDTYPE_TGID gets used to it's fullest.  The long term potential
is allowing zombie thread group leaders to exit, which will remove
a lot more special cases in the code.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 10:43:12 -05:00
Thomas Gleixner
c6bb11147e Merge branch 'fortglx/4.19/time' of https://git.linaro.org/people/john.stultz/linux into timers/core
Pull timekeeping updates from John Stultz:

  - Make the timekeeping update more precise when NTP frequency is set
    directly by updating the multiplier.

  - Adjust selftests
2018-07-12 22:19:58 +02:00
Thomas Gleixner
78c9c4dfbf posix-timers: Sanitize overrun handling
The posix timer overrun handling is broken because the forwarding functions
can return a huge number of overruns which does not fit in an int. As a
consequence timer_getoverrun(2) and siginfo::si_overrun can turn into
random number generators.

The k_clock::timer_forward() callbacks return a 64 bit value now. Make
k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal
accounting is correct. 3Remove the temporary (int) casts.

Add a helper function which clamps the overrun value returned to user space
via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value
between 0 and INT_MAX. INT_MAX is an indicator for user space that the
overrun value has been clamped.

Reported-by: Team OWL337 <icytxw@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de
2018-07-02 11:33:25 +02:00
Sebastian Andrzej Siewior
c60c32a577 posix-cpu-timers: Remove lockdep_assert_irqs_disabled()
The lockdep_assert_irqs_disabled() was a BUG_ON() statement in the
beginning and it was added just before the "spin_lock(siglock)"
statement to ensure this lock was taken with disabled interrupts.

This is no longer the case: the siglock is acquired via
lock_task_sighand() and this function already disables the interrupts.
The lock is also acquired before this "lockdep_assert_irqs_disabled" so
it is best to remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r20180504152548.7166-1-bigeasy@linutronix.de
2018-06-12 17:18:37 +02:00
Laura Abbott
c3bca5d450 posix-cpu-timers: Ensure set_process_cpu_timer is always evaluated
Commit a9445e47d8 ("posix-cpu-timers: Make set_process_cpu_timer()
more robust") moved the check into the 'if' statement. Unfortunately,
it did so on the right side of an && which means that it may get short
circuited and never evaluated. This is easily reproduced with:

$ cat loop.c
void main() {
  struct rlimit res;
  /* set the CPU time limit */
  getrlimit(RLIMIT_CPU,&res);
  res.rlim_cur = 2;
  res.rlim_max = 2;
  setrlimit(RLIMIT_CPU,&res);

  while (1);
}

Which will hang forever instead of being killed. Fix this by pulling the
evaluation out of the if statement but checking the return value instead.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1568337
Fixes: a9445e47d8 ("posix-cpu-timers: Make set_process_cpu_timer() more robust")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: "Max R . P . Grossmann" <m@max.pm>
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lkml.kernel.org/r/20180417215742.2521-1-labbott@redhat.com
2018-04-19 12:54:57 +02:00
Linus Torvalds
af8c5e2d60 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Implement frequency/CPU invariance and OPP selection for
     SCHED_DEADLINE (Juri Lelli)

   - Tweak the task migration logic for better multi-tasking
     workload scalability (Mel Gorman)

   - Misc cleanups, fixes and improvements"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/deadline: Make bandwidth enforcement scale-invariant
  sched/cpufreq: Move arch_scale_{freq,cpu}_capacity() outside of #ifdef CONFIG_SMP
  sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter
  sched/cpufreq: Always consider all CPUs when deciding next freq
  sched/cpufreq: Split utilization signals
  sched/cpufreq: Change the worker kthread to SCHED_DEADLINE
  sched/deadline: Move CPU frequency selection triggering points
  sched/cpufreq: Use the DEADLINE utilization signal
  sched/deadline: Implement "runtime overrun signal" support
  sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache
  sched/fair: Correct obsolete comment about cpufreq_update_util()
  sched/fair: Remove impossible condition from find_idlest_group_cpu()
  sched/cpufreq: Don't pass flags to sugov_set_iowait_boost()
  sched/cpufreq: Initialize sg_cpu->flags to 0
  sched/fair: Consider RT/IRQ pressure in capacity_spare_wake()
  sched/fair: Use 'unsigned long' for utilization, consistently
  sched/core: Rework and clarify prepare_lock_switch()
  sched/fair: Remove unused 'curr' parameter from wakeup_gran
  sched/headers: Constify object_is_on_stack()
2018-01-30 11:55:56 -08:00
Max R. P. Grossmann
a9445e47d8 posix-cpu-timers: Make set_process_cpu_timer() more robust
Because the return value of cpu_timer_sample_group() is not checked,
compilers and static checkers can legitimately warn about a potential use
of the uninitialized variable 'now'. This is not a runtime issue as all call
sites hand in valid clock ids.

Also cpu_timer_sample_group() is invoked unconditionally even when the
result is not used because *oldval is NULL.

Make the invocation conditional and check the return value.

[ tglx: Massage changelog ]

Signed-off-by: Max R. P. Grossmann <m@max.pm>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john.stultz@linaro.org
Link: https://lkml.kernel.org/r/20180108190157.10048-1-m@max.pm
2018-01-14 20:50:59 +01:00
Juri Lelli
34be39305a sched/deadline: Implement "runtime overrun signal" support
This patch adds the possibility of getting the delivery of a SIGXCPU
signal whenever there is a runtime overrun. The request is done through
the sched_flags field within the sched_attr structure.

Forward port of https://lkml.org/lkml/2009/10/16/170

Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Luca Abeni <luca.abeni@santannapisa.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Link: http://lkml.kernel.org/r/1513077024-25461-1-git-send-email-claudio@evidence.eu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-10 11:30:31 +01:00
Nick Desaulniers
29f1b2b0fe posix-timers: Prevent UB from shifting negative signed value
Shifting a negative signed number is undefined behavior. Looking at the
macros MAKE_PROCESS_CPUCLOCK and FD_TO_CLOCKID, it seems that the
subexpression:

(~(clockid_t) (pid) << 3)

where clockid_t resolves to a signed int, which once negated, is
undefined behavior to shift the value of if the results thus far are
negative.

It was further suggested to make these macros into inline functions.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kselftest@vger.kernel.org
Cc: Shuah Khan <shuah@kernel.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Link: https://lkml.kernel.org/r/1514517100-18051-1-git-send-email-nick.desaulniers@gmail.com
2018-01-04 14:57:10 +01:00
Frederic Weisbecker
a69682200d timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled
Use lockdep to check that IRQs are enabled or disabled as expected. This
way the sanity check only shows overhead when concurrency correctness
debug code is enabled.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David S . Miller <davem@davemloft.net>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1509980490-4285-13-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-08 11:13:54 +01:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Krzysztof Opasiak
3cf294962d posix-cpu-timers: Use dedicated helper to access rlimit values
Use rlimit() and rlimit_max() helper instead of manually writing
whole chain from task to rlimit value

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170705172548.7911-1-k.opasiak@samsung.com
2017-08-18 12:44:42 +02:00
Linus Torvalds
ea3b25e132 Merge branch 'timers-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull timer-related user access updates from Al Viro:
 "Continuation of timers-related stuff (there had been more, but my
  parts of that series are already merged via timers/core). This is more
  of y2038 work by Deepa Dinamani, partially disrupted by the
  unification of native and compat timers-related syscalls"

* 'timers-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  posix_clocks: Use get_itimerspec64() and put_itimerspec64()
  timerfd: Use get_itimerspec64() and put_itimerspec64()
  nanosleep: Use get_timespec64() and put_timespec64()
  posix-timers: Use get_timespec64() and put_timespec64()
  posix-stubs: Conditionally include COMPAT_SYS_NI defines
  time: introduce {get,put}_itimerspec64
  time: add get_timespec64 and put_timespec64
2017-07-05 15:34:35 -07:00
Deepa Dinamani
c0edd7c9ac nanosleep: Use get_timespec64() and put_timespec64()
Usage of these apis and their compat versions makes
the syscalls: clock_nanosleep and nanosleep and
their compat implementations simpler.

This is a preparatory patch to isolate data conversions to
struct timespec64 at userspace boundaries. This helps contain
the changes needed to transition to new y2038 safe types.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-30 04:14:14 -04:00
Thomas Gleixner
098b0e01a9 posix-cpu-timers: Make timespec to nsec conversion safe
The expiry time of a posix cpu timer is supplied through sys_timer_set()
via a struct timespec. The timespec is validated for correctness.

In the actual set timer implementation the timespec is converted to a
scalar nanoseconds value. If the tv_sec part of the time spec is large
enough the conversion to nanoseconds (sec * NSEC_PER_SEC) overflows 64bit.

Mitigate that by using the timespec_to_ktime() conversion function, which
checks the tv_sec part for a potential mult overflow and clamps the result
to KTIME_MAX, which is about 292 years. 

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170620154113.588276707@linutronix.de
2017-06-20 21:33:56 +02:00
Thomas Gleixner
938e7cf2d5 posix-timers: Make nanosleep timespec argument const
No nanosleep implementation modifies the rqtp argument. Mark is const.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
2017-06-14 00:00:47 +02:00
Thomas Gleixner
343d8fc208 posix-cpu-timers: Avoid timespec conversion in do_cpu_nanosleep()
No point in converting the expiry time back and forth.

No point either to update the value in the caller supplied variable. mark
the rqtp argument const.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
2017-06-14 00:00:46 +02:00
Al Viro
fb923c4a3c posix-timers: Kill ->nsleep_restart()
No more users.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-8-viro@ZenIV.linux.org.uk
2017-06-14 00:00:42 +02:00