This is a note to let you know that I've just added the patch titled
sched: Collate affine_move_task() stoppers
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-collate-affine_move_task-stoppers.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 58b1a45086b5f80f2b2842aa7ed0da51a64a302b Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed, 24 Feb 2021 11:15:23 +0100
Subject: sched: Collate affine_move_task() stoppers
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 58b1a45086b5f80f2b2842aa7ed0da51a64a302b upstream.
The SCA_MIGRATE_ENABLE and task_running() cases are almost identical,
collapse them to avoid further duplication.
Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
Cc: stable@xxxxxxxxxx
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Valentin Schneider <valentin.schneider@xxxxxxx>
Link: https://lkml.kernel.org/r/20210224131355.500108964@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/core.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2279,30 +2279,23 @@ static int affine_move_task(struct rq *r
return -EINVAL;
}
- if (flags & SCA_MIGRATE_ENABLE) {
-
- refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
- p->migration_flags &= ~MDF_PUSH;
- task_rq_unlock(rq, p, rf);
-
- stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
- &pending->arg, &pending->stop_work);
-
- return 0;
- }
-
if (task_running(rq, p) || p->state == TASK_WAKING) {
/*
- * Lessen races (and headaches) by delegating
- * is_migration_disabled(p) checks to the stopper, which will
- * run on the same CPU as said p.
+ * MIGRATE_ENABLE gets here because 'p == current', but for
+ * anything else we cannot do is_migration_disabled(), punt
+ * and have the stopper function handle it all race-free.
*/
+
refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+ if (flags & SCA_MIGRATE_ENABLE)
+ p->migration_flags &= ~MDF_PUSH;
task_rq_unlock(rq, p, rf);
stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
&pending->arg, &pending->stop_work);
+ if (flags & SCA_MIGRATE_ENABLE)
+ return 0;
} else {
if (!is_migration_disabled(p)) {
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.11/powerpc-perf-fix-handling-of-privilege-level-checks-in-perf-interrupt-context.patch
queue-5.11/sched-fix-migration_cpu_stop-requeueing.patch
queue-5.11/sched-simplify-set_affinity_pending-refcounts.patch
queue-5.11/perf-traceevent-ensure-read-cmdlines-are-null-terminated.patch
queue-5.11/perf-core-flush-pmu-internal-buffers-for-per-cpu-eve.patch
queue-5.11/sched-simplify-migration_cpu_stop.patch
queue-5.11/sched-membarrier-fix-missing-local-execution-of-ipi_sync_rq_state.patch
queue-5.11/x86-unwind-orc-disable-kasan-checking-in-the-orc-unwinder-part-2.patch
queue-5.11/arm64-perf-fix-64-bit-event-counter-read-truncation.patch
queue-5.11/sched-collate-affine_move_task-stoppers.patch
queue-5.11/sched-fix-affine_move_task-self-concurrency.patch
queue-5.11/stop_machine-mark-helpers-__always_inline.patch
queue-5.11/seqlock-lockdep-fix-seqcount_latch_init.patch
queue-5.11/sched-optimize-migration_cpu_stop.patch
queue-5.11/perf-build-fix-ccache-usage-in-cc-when-generating-arch-errno-table.patch
queue-5.11/mm-userfaultfd-fix-memory-corruption-due-to-writeprotect.patch
queue-5.11/perf-x86-intel-set-perf_attach_sched_cb-for-large-pe.patch
