diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-08-28 16:55:52 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-09-09 12:27:23 +0300 |
| commit | 868ad33bfa3bf39960982682ad3a0f8ebda1656e (patch) | |
| tree | a45decc6622e9ca567a6b9b5ae726df9cc0bcbc3 /kernel/sched/core.c | |
| parent | 9848417926353daa59d2b05eb26e185063dbac6e (diff) | |
| download | linux-868ad33bfa3bf39960982682ad3a0f8ebda1656e.tar.xz | |
sched: Prevent balance_push() on remote runqueues
sched_setscheduler() and rt_mutex_setprio() invoke the run-queue balance
callback after changing priorities or the scheduling class of a task. The
run-queue for which the callback is invoked can be local or remote.
That's not a problem for the regular rq::push_work which is serialized with
a busy flag in the run-queue struct, but for the balance_push() work which
is only valid to be invoked on the outgoing CPU that's wrong. It not only
triggers the debug warning, but also leaves the per CPU variable push_work
unprotected, which can result in double enqueues on the stop machine list.
Remove the warning and validate that the function is invoked on the
outgoing CPU.
Fixes: ae7927023243 ("sched: Optimize finish_lock_switch()")
Reported-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87zgt1hdw7.ffs@tglx
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f3b27c6c5153..b21a1857b75a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8523,7 +8523,6 @@ static void balance_push(struct rq *rq) struct task_struct *push_task = rq->curr; lockdep_assert_rq_held(rq); - SCHED_WARN_ON(rq->cpu != smp_processor_id()); /* * Ensure the thing is persistent until balance_push_set(.on = false); @@ -8531,9 +8530,10 @@ static void balance_push(struct rq *rq) rq->balance_callback = &balance_push_callback; /* - * Only active while going offline. + * Only active while going offline and when invoked on the outgoing + * CPU. */ - if (!cpu_dying(rq->cpu)) + if (!cpu_dying(rq->cpu) || rq != this_rq()) return; /* |