linux-stable.git/kernel/rcu, branch v5.9.2

refperf: Avoid null pointer dereference when buf fails to allocate

2020-10-29T09:11:38+00:00

[ Upstream commit 58db5785b0d76be4582a32a7900acce88e691d36 ]

Currently in the unlikely event that buf fails to be allocated it
is dereferenced a few times.  Use the errexit flag to determine if
buf should be written to to avoid the null pointer dereferences.

Addresses-Coverity: ("Dereference after null check")
Fixes: f518f154ecef ("refperf: Dynamically allocate experiment-summary output buffer")
Signed-off-by: Colin Ian King 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin

rcutorture: Properly set rcu_fwds for OOM handling

2020-10-29T09:11:38+00:00

[ Upstream commit c8fa63714763b7795a3f5fb7ed6d000763e6dccc ]

The conversion of rcu_fwds to dynamic allocation failed to actually
allocate the required structure.  This commit therefore allocates it,
frees it, and updates rcu_fwds accordingly.  While in the area, it
abstracts the cleanup actions into rcu_torture_fwd_prog_cleanup().

Fixes: 5155be9994e5 ("rcutorture: Dynamically allocate rcu_fwds structure")
Reported-by: kernel test robot 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin

rcu/tree: Force quiescent state on callback overload

2020-10-29T09:11:38+00:00

[ Upstream commit 9c39245382de4d52a122641952900709d4a9950b ]

On callback overload, it is necessary to quickly detect idle CPUs,
and rcu_gp_fqs_check_wake() checks for this condition.  Unfortunately,
the code following the call to this function does not repeat this check,
which means that in reality no actual quiescent-state forcing, instead
only a couple of quick and pointless wakeups at the beginning of the
grace period.

This commit therefore adds a check for the RCU_GP_FLAG_OVLD flag in
the post-wakeup "if" statement in rcu_gp_fqs_loop().

Fixes: 1fca4d12f4637 ("rcu: Expedite first two FQS scans under callback-overload conditions")
Reviewed-by: Joel Fernandes (Google) 
Signed-off-by: Neeraj Upadhyay 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin

Merge tag 'pm-5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2020-09-25T17:39:22+00:00

Pull power management fixes from Rafael Wysocki:
 "These fix more fallout of recent RCU-lockdep changes in CPU idle code
  and two devfreq issues.

  Specifics:

   - Export rcu_idle_{enter,exit} to modules to fix build issues
     introduced by recent RCU-lockdep fixes (Borislav Petkov)

   - Add missing return statement to a stub function in the ACPI
     processor driver to fix a build issue introduced by recent
     RCU-lockdep fixes (Rafael Wysocki)

   - Fix recently introduced suspicious RCU usage warnings in the PSCI
     cpuidle driver and drop stale comments regarding RCU_NONIDLE()
     usage from enter_s2idle_proper() (Ulf Hansson)

   - Fix error code path in the tegra30 devfreq driver (Dan Carpenter)

   - Add missing information to devfreq_summary debugfs (Chanwoo Choi)"

* tag 'pm-5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: processor: Fix build for ARCH_APICTIMER_STOPS_ON_C3 unset
  PM / devfreq: tegra30: Disable clock on error in probe
  PM / devfreq: Add timer type to devfreq_summary debugfs
  cpuidle: Drop misleading comments about RCU usage
  cpuidle: psci: Fix suspicious RCU usage
  rcu/tree: Export rcu_idle_{enter,exit} to modules

rcu/tree: Export rcu_idle_{enter,exit} to modules

2020-09-21T13:37:21+00:00

Fix this link error:

  ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
  ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!

when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light
of ARM needing those soon too, they should simply be exported.

Fixes: 1fecfdbb7acc ("ACPI: processor: Take over RCU-idle for C3-BM idle")
Reported-by: Sven Joachim 
Suggested-by: Peter Zijlstra 
Signed-off-by: Borislav Petkov 
Reviewed-by: Paul E. McKenney 
Signed-off-by: Rafael J. Wysocki

rcu-tasks: Prevent complaints of unused show_rcu_tasks_classic_gp_kthread()

2020-09-16T23:32:36+00:00

Commit 8344496e8b49 ("rcu-tasks: Conditionally compile
show_rcu_tasks_gp_kthreads()") introduced conditional
compilation of several functions, but forgot one occurrence of
show_rcu_tasks_classic_gp_kthread() that causes the compiler to warn of
an unused static function.  This commit uses "static inline" to avoid
these complaints and possibly also to avoid emitting an actual definition
of this function.

Fixes: 8344496e8b49 ("rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads()")
Cc:  # 5.8.x
Reported-by: Laurent Pinchart 
Signed-off-by: Paul E. McKenney

rcu: kasan: record and print call_rcu() call stack

2020-08-07T18:33:28+00:00

Patch series "kasan: memorize and print call_rcu stack", v8.

This patchset improves KASAN reports by making them to have call_rcu()
call stack information.  It is useful for programmers to solve
use-after-free or double-free memory issue.

The KASAN report was as follows(cleaned up slightly):

BUG: KASAN: use-after-free in kasan_rcu_reclaim+0x58/0x60

Freed by task 0:
 kasan_save_stack+0x24/0x50
 kasan_set_track+0x24/0x38
 kasan_set_free_info+0x18/0x20
 __kasan_slab_free+0x10c/0x170
 kasan_slab_free+0x10/0x18
 kfree+0x98/0x270
 kasan_rcu_reclaim+0x1c/0x60

Last call_rcu():
 kasan_save_stack+0x24/0x50
 kasan_record_aux_stack+0xbc/0xd0
 call_rcu+0x8c/0x580
 kasan_rcu_uaf+0xf4/0xf8

Generic KASAN will record the last two call_rcu() call stacks and print up
to 2 call_rcu() call stacks in KASAN report.  it is only suitable for
generic KASAN.

This feature considers the size of struct kasan_alloc_meta and
kasan_free_meta, we try to optimize the structure layout and size, lets it
get better memory consumption.

[1]https://bugzilla.kernel.org/show_bug.cgi?id=198437
[2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ

This patch (of 4):

This feature will record the last two call_rcu() call stacks and prints up
to 2 call_rcu() call stacks in KASAN report.

When call_rcu() is called, we store the call_rcu() call stack into slub
alloc meta-data, so that the KASAN report can print rcu stack.

[1]https://bugzilla.kernel.org/show_bug.cgi?id=198437
[2]https://groups.google.com/forum/#!searchin/kasan-dev/better$20stack$20traces$20for$20rcu%7Csort:date/kasan-dev/KQsjT_88hDE/7rNUZprRBgAJ

[walter-zh.wu@mediatek.com: build fix]
  Link: http://lkml.kernel.org/r/20200710162401.23816-1-walter-zh.wu@mediatek.com

Suggested-by: Dmitry Vyukov 
Signed-off-by: Walter Wu 
Signed-off-by: Andrew Morton 
Tested-by: Dmitry Vyukov 
Reviewed-by: Dmitry Vyukov 
Reviewed-by: Andrey Konovalov 
Acked-by: Paul E. McKenney 
Cc: Andrey Ryabinin 
Cc: Alexander Potapenko 
Cc: Josh Triplett 
Cc: Mathieu Desnoyers 
Cc: Lai Jiangshan 
Cc: Joel Fernandes 
Cc: Jonathan Corbet 
Cc: Matthias Brugger 
Link: http://lkml.kernel.org/r/20200710162123.23713-1-walter-zh.wu@mediatek.com
Link: http://lkml.kernel.org/r/20200601050847.1096-1-walter-zh.wu@mediatek.com
Link: http://lkml.kernel.org/r/20200601050927.1153-1-walter-zh.wu@mediatek.com
Signed-off-by: Linus Torvalds

Merge tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-08-06T18:55:43+00:00

Pull sched/fifo updates from Ingo Molnar:
 "This adds the sched_set_fifo*() encapsulation APIs to remove static
  priority level knowledge from non-scheduler code.

  The three APIs for non-scheduler code to set SCHED_FIFO are:

   - sched_set_fifo()
   - sched_set_fifo_low()
   - sched_set_normal()

  These are two FIFO priority levels: default (high), and a 'low'
  priority level, plus sched_set_normal() to set the policy back to
  non-SCHED_FIFO.

  Since the changes affect a lot of non-scheduler code, we kept this in
  a separate tree"

* tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  sched,tracing: Convert to sched_set_fifo()
  sched: Remove sched_set_*() return value
  sched: Remove sched_setscheduler*() EXPORTs
  sched,psi: Convert to sched_set_fifo_low()
  sched,rcutorture: Convert to sched_set_fifo_low()
  sched,rcuperf: Convert to sched_set_fifo_low()
  sched,locktorture: Convert to sched_set_fifo()
  sched,irq: Convert to sched_set_fifo()
  sched,watchdog: Convert to sched_set_fifo()
  sched,serial: Convert to sched_set_fifo()
  sched,powerclamp: Convert to sched_set_fifo()
  sched,ion: Convert to sched_set_normal()
  sched,powercap: Convert to sched_set_fifo*()
  sched,spi: Convert to sched_set_fifo*()
  sched,mmc: Convert to sched_set_fifo*()
  sched,ivtv: Convert to sched_set_fifo*()
  sched,drm/scheduler: Convert to sched_set_fifo*()
  sched,msm: Convert to sched_set_fifo*()
  sched,psci: Convert to sched_set_fifo*()
  sched,drbd: Convert to sched_set_fifo*()
  ...

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

2020-07-30T22:15:53+00:00

Pull the v5.9 RCU bits from Paul E. McKenney:

 - Documentation updates
 - Miscellaneous fixes
 - kfree_rcu updates
 - RCU tasks updates
 - Read-side scalability tests
 - SRCU updates
 - Torture-test updates

Signed-off-by: Ingo Molnar

Merge tag 'core-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-07-05T19:21:28+00:00

Pull rcu fixlet from Thomas Gleixner:
 "A single fix for a printk format warning in RCU"

* tag 'core-urgent-2020-07-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcuperf: Fix printk format warning