linux/kernel/sched
Linus Torvalds 33e83ffe4c A few scheduler fixes:
- Plug a race between pick_next_task_fair() and try_to_wake_up() where
    both try to write to the same task, even though both paths hold a
    runqueue lock, but obviously from different runqueues.
 
    The problem is that the store to task::on_rq in __block_task() is
    visible to try_to_wake_up() which assumes that the task is not queued.
    Both sides then operate on the same task.
 
    Cure it by rearranging __block_task() so the the store to task::on_rq is
    the last operation on the task.
 
  - Prevent a potential NULL pointer dereference in task_numa_work()
 
    task_numa_work() iterates the VMAs of a process. A concurrent unmap of
    the address space can result in a NULL pointer return from vma_next()
    which is unchecked.
 
    Add the missing NULL pointer check to prevent this.
 
  - Operate on the correct scheduler policy in task_should_scx()
 
    task_should_scx() returns true when a task should be handled by sched
    EXT. It checks the tasks scheduling policy.
 
    This fails when the check is done before a policy has been set.
 
    Cure it by handing the policy into task_should_scx() so it operates
    on the requested value.
 
  - Add the missing handling of sched EXT in the delayed dequeue
    mechanism. This was simply forgotten.
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Merge tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Thomas Gleixner:

 - Plug a race between pick_next_task_fair() and try_to_wake_up() where
   both try to write to the same task, even though both paths hold a
   runqueue lock, but obviously from different runqueues.

   The problem is that the store to task::on_rq in __block_task() is
   visible to try_to_wake_up() which assumes that the task is not
   queued. Both sides then operate on the same task.

   Cure it by rearranging __block_task() so the the store to task::on_rq
   is the last operation on the task.

 - Prevent a potential NULL pointer dereference in task_numa_work()

   task_numa_work() iterates the VMAs of a process. A concurrent unmap
   of the address space can result in a NULL pointer return from
   vma_next() which is unchecked.

   Add the missing NULL pointer check to prevent this.

 - Operate on the correct scheduler policy in task_should_scx()

   task_should_scx() returns true when a task should be handled by sched
   EXT. It checks the tasks scheduling policy.

   This fails when the check is done before a policy has been set.

   Cure it by handing the policy into task_should_scx() so it operates
   on the requested value.

 - Add the missing handling of sched EXT in the delayed dequeue
   mechanism. This was simply forgotten.

* tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/ext: Fix scx vs sched_delayed
  sched: Pass correct scheduling policy to __setscheduler_class
  sched/numa: Fix the potential null pointer dereference in task_numa_work()
  sched: Fix pick_next_task_fair() vs try_to_wake_up() race
2024-11-03 08:18:28 -10:00
..
autogroup.c scheduler: Remove the now superfluous sentinel elements from ctl_table array 2024-04-24 09:43:54 +02:00
autogroup.h
build_policy.c sched_ext: Disallow loading BPF scheduler if isolcpus= domain isolation is in effect 2024-07-08 09:30:13 -10:00
build_utility.c sched/headers: Remove duplicate header inclusions 2023-10-03 21:27:55 +02:00
clock.c sched: Fix spelling in comments 2024-05-27 17:00:21 +02:00
completion.c sched: add a few helpers to wake up tasks on the current cpu 2023-07-17 16:08:08 -07:00
core_sched.c sched: Fix spelling in comments 2024-05-27 17:00:21 +02:00
core.c sched: Pass correct scheduling policy to __setscheduler_class 2024-10-29 13:57:51 +01:00
cpuacct.c Merge branch 'sched/fast-headers' into sched/core 2022-03-15 09:05:05 +01:00
cpudeadline.c sched/topology: Consolidate and clean up access to a CPU's max compute capacity 2023-10-09 12:59:48 +02:00
cpudeadline.h
cpufreq_schedutil.c Merge branch 'tip/sched/core' into sched_ext/for-6.12 2024-09-11 08:43:26 -10:00
cpufreq.c sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
cpupri.c sched/rt: Fix live lock between select_fallback_rq() and RT push 2023-09-28 22:58:13 +02:00
cpupri.h
cputime.c sched/cputime: Fix mul_u64_u64_div_u64() precision for cputime 2024-07-29 12:22:32 +02:00
deadline.c sched/deadline: Use hrtick_enabled_dl() before start_hrtick_dl() 2024-10-11 10:49:32 +02:00
debug.c Merge branch 'tip/sched/core' into sched_ext/for-6.12 2024-09-11 08:43:26 -10:00
ext.c A few scheduler fixes: 2024-11-03 08:18:28 -10:00
ext.h sched: Pass correct scheduling policy to __setscheduler_class 2024-10-29 13:57:51 +01:00
fair.c sched/numa: Fix the potential null pointer dereference in task_numa_work() 2024-10-26 09:28:37 +02:00
features.h sched/eevdf: Allow shorter slices to wakeup-preempt 2024-08-17 11:06:45 +02:00
idle.c Merge branch 'tip/sched/core' into for-6.12 2024-09-03 12:49:18 -10:00
isolation.c sched/isolation: Fix boot crash when maxcpus < first housekeeping CPU 2024-04-28 10:08:21 +02:00
loadavg.c sched: Fix spelling in comments 2024-05-27 17:00:21 +02:00
Makefile sched/headers: Introduce kernel/sched/build_policy.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
membarrier.c RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
pelt.c sched: Move update_other_load_avgs() to kernel/sched/pelt.c 2024-09-11 20:00:21 -10:00
pelt.h sched: Move update_other_load_avgs() to kernel/sched/pelt.c 2024-09-11 20:00:21 -10:00
psi.c sched: psi: fix bogus pressure spikes from aggregation race 2024-10-03 16:03:16 -07:00
rt.c sched: Add put_prev_task(.next) 2024-09-03 15:26:32 +02:00
sched-pelt.h
sched.h sched: Pass correct scheduling policy to __setscheduler_class 2024-10-29 13:57:51 +01:00
smp.h sched, smp: Trace smp callback causing an IPI 2023-03-24 11:01:29 +01:00
stats.c profiling: remove profile=sleep support 2024-08-04 13:36:28 -07:00
stats.h sched/psi: Fix mistaken CPU pressure indication after corrupted task state bug 2024-10-14 09:11:42 +02:00
stop_task.c sched: Add put_prev_task(.next) 2024-09-03 15:26:32 +02:00
swait.c sched: add a few helpers to wake up tasks on the current cpu 2023-07-17 16:08:08 -07:00
syscalls.c sched: Pass correct scheduling policy to __setscheduler_class 2024-10-29 13:57:51 +01:00
topology.c sched/fair: Fair server interface 2024-07-29 12:22:36 +02:00
wait_bit.c sched: Fix spelling in comments 2024-05-27 17:00:21 +02:00
wait.c sched: remove wait bookmarks 2023-10-18 14:34:18 -07:00