linux.git/kernel/sched, branch v4.7-rc4

Merge branch 'stacking-fixes' (vfs stacking fixes from Jann)

2016-06-10T19:10:02+00:00

Merge filesystem stacking fixes from Jann Horn.

* emailed patches from Jann Horn :
  sched: panic on corrupted stack end
  ecryptfs: forbid opening files without mmap handler
  proc: prevent stacking filesystems on top

sched: panic on corrupted stack end

2016-06-10T19:09:43+00:00

Until now, hitting this BUG_ON caused a recursive oops (because oops
handling involves do_exit(), which calls into the scheduler, which in
turn raises an oops), which caused stuff below the stack to be
overwritten until a panic happened (e.g.  via an oops in interrupt
context, caused by the overwritten CPU index in the thread_info).

Just panic directly.

Signed-off-by: Jann Horn 
Signed-off-by: Linus Torvalds

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-06-10T18:24:39+00:00

Pull scheduler fixes from Ingo Molnar:
 "Two scheduler debugging fixes"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix 'schedstats=enable' cmdline option
  sched/debug: Fix /proc/sched_debug regression

Merge branches 'pm-cpufreq-fixes' and 'pm-cpuidle'

2016-06-09T21:49:16+00:00

* pm-cpufreq-fixes:
  cpufreq: intel_pstate: Fix ->set_policy() interface for no_turbo
  cpufreq: intel_pstate: Fix code ordering in intel_pstate_set_policy()

* pm-cpuidle:
  cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE

sched/debug: Fix 'schedstats=enable' cmdline option

2016-06-08T12:33:05+00:00

The 'schedstats=enable' option doesn't work, and also produces the
following warning during boot:

  WARNING: CPU: 0 PID: 0 at /home/jpoimboe/git/linux/kernel/jump_label.c:61 static_key_slow_inc+0x8c/0xa0
  static_key_slow_inc used before call to jump_label_init
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 4.7.0-rc1+ #25
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
   0000000000000086 3ae3475a4bea95d4 ffffffff81e03da8 ffffffff8143fc83
   ffffffff81e03df8 0000000000000000 ffffffff81e03de8 ffffffff810b1ffb
   0000003d00000096 ffffffff823514d0 ffff88007ff197c8 0000000000000000
  Call Trace:
   [] dump_stack+0x85/0xc2
   [] __warn+0xcb/0xf0
   [] warn_slowpath_fmt+0x5f/0x80
   [] static_key_slow_inc+0x8c/0xa0
   [] static_key_enable+0x16/0x40
   [] setup_schedstats+0x29/0x94
   [] unknown_bootoption+0x89/0x191
   [] parse_args+0x297/0x4b0
   [] start_kernel+0x1d8/0x4a9
   [] ? set_init_arg+0x55/0x55
   [] ? early_idt_handler_array+0x120/0x120
   [] x86_64_start_reservations+0x2f/0x31
   [] x86_64_start_kernel+0x14a/0x16d

The problem is that it tries to update the 'sched_schedstats' static key
before jump labels have been initialized.

Changing jump_label_init() to be called earlier before
parse_early_param() wouldn't fix it: it would still fail trying to
poke_text() because mm isn't yet initialized.

Instead, just create a temporary '__sched_schedstats' variable which can
be copied to the static key later during sched_init() after jump labels
have been initialized.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Matt Fleming 
Cc: Mel Gorman 
Cc: Peter Zijlstra 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Fixes: cb2517653fcc ("sched/debug: Make schedstats a runtime tunable that is disabled by default")
Link: http://lkml.kernel.org/r/453775fe3433bed65731a583e228ccea806d18cd.1465322027.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

sched/debug: Fix /proc/sched_debug regression

2016-06-08T12:31:58+00:00

Commit:

  cb2517653fcc ("sched/debug: Make schedstats a runtime tunable that is disabled by default")

... introduced a bug when CONFIG_SCHEDSTATS is enabled and the
runtime tunable is disabled (which is the default).

The wait-time, sum-exec, and sum-sleep fields are missing from the
/proc/sched_debug file in the runnable_tasks section.

Fix it with a new schedstat_val() macro which returns the field value
when schedstats is enabled and zero otherwise.  The macro works with
both SCHEDSTATS and !SCHEDSTATS.  I put the macro in stats.h since it
might end up being useful in other places.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Mel Gorman 
Cc: Linus Torvalds 
Cc: Matt Fleming 
Cc: Peter Zijlstra 
Cc: Srikar Dronamraju 
Cc: Thomas Gleixner 
Fixes: cb2517653fcc ("sched/debug: Make schedstats a runtime tunable that is disabled by default")
Link: http://lkml.kernel.org/r/bcda7c2790cf2ccbe586a28c02dd7b6fe7749a2b.1464994423.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE

2016-06-02T21:05:27+00:00

The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop")
removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
compiler optimising away __this_cpu_read(cpuidle_devices). However, with
CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
and the kernel fails to link since cpuidle_devices is not defined.

This patch introduces an accessor function for the current CPU cpuidle
device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
cpuidle_idle_call().

Signed-off-by: Catalin Marinas 
Cc: 4.5+  # 4.5+
Signed-off-by: Rafael J. Wysocki

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-05-26T00:11:43+00:00

Pull scheduler fixes from Ingo Molnar:
 "Two fixes: one for a lost wakeup, the other to fix the compiler
  optimizing out preempt operations on ARM64 (and possibly other non-x86
  architectures)"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix remote wakeups
  sched/preempt: Fix preempt_count manipulations

Merge branches 'pm-cpufreq', 'pm-cpuidle' and 'pm-core'

2016-05-25T19:54:45+00:00

* pm-cpufreq:
  cpufreq: schedutil: Improve prints messages with pr_fmt
  cpufreq: simplified goto out in cpufreq_register_driver()
  cpufreq: governor: CPUFREQ_GOV_STOP never fails
  cpufreq: governor: CPUFREQ_GOV_POLICY_EXIT never fails
  intel_pstate: Simplify conditional in intel_pstate_set_policy()

* pm-cpuidle:
  cpuidle: Fix cpuidle_state_is_coupled() argument in cpuidle_enter()

* pm-core:
  PM / sleep: Handle failures in device_suspend_late() consistently

sched/core: Fix remote wakeups

2016-05-25T06:35:18+00:00

Commit:

  b5179ac70de8 ("sched/fair: Prepare to fix fairness problems on migration")

... introduced a bug: Mike Galbraith found that it introduced a
performance regression, while Paul E. McKenney reported lost
wakeups and bisected it to this commit.

The reason is that I mis-read ttwu_queue() such that I assumed any
wakeup that got a remote queue must have had the task migrated.

Since this is not so; we need to transfer this information between
queueing the wakeup and actually doing the wakeup. Use a new
task_struct::sched_flag for this, we already write to
sched_contributes_to_load in the wakeup path so this is a hot and
modified cacheline.

Reported-by: Paul E. McKenney 
Reported-by: Mike Galbraith 
Tested-by: Mike Galbraith 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Hunter 
Cc: Andy Lutomirski 
Cc: Ben Segall 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: Fenghua Yu 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Matt Fleming 
Cc: Morten Rasmussen 
Cc: Oleg Nesterov 
Cc: Paul Turner 
Cc: Pavan Kondeti 
Cc: Peter Zijlstra 
Cc: Quentin Casasnovas 
Cc: Thomas Gleixner 
Cc: byungchul.park@lge.com
Fixes: b5179ac70de8 ("sched/fair: Prepare to fix fairness problems on migration")
Link: http://lkml.kernel.org/r/20160523091907.GD15728@worktop.ger.corp.intel.com
Signed-off-by: Ingo Molnar