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| author | Wanpeng Li <wanpeng.li@hotmail.com> | 2016-08-04 03:42:20 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-10 14:02:55 +0200 |
| commit | c0c8c9fa210c9a042060435f17e40ba4a76d6d6f (patch) | |
| tree | 039bc9a7711ddf47c3c4a7afa324102030e791d4 /kernel | |
| parent | sched/cputime: Mitigate performance regression in times()/clock_gettime() (diff) | |
| download | linux-c0c8c9fa210c9a042060435f17e40ba4a76d6d6f.tar.xz linux-c0c8c9fa210c9a042060435f17e40ba4a76d6d6f.zip | |
sched/deadline: Fix lock pinning warning during CPU hotplug
The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
releasing a pinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
? dl_task_timer+0x1a1/0x2b0
warn_slowpath_fmt+0x4f/0x60
? sched_clock+0x13/0x20
lock_release+0x690/0x6a0
? enqueue_pushable_dl_task+0x9b/0xa0
? enqueue_task_dl+0x1ca/0x480
_raw_spin_unlock+0x1f/0x40
dl_task_timer+0x1a1/0x2b0
? push_dl_task.part.31+0x190/0x190
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
unpinning an unpinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_fmt+0x4f/0x60
lock_unpin_lock+0x181/0x1a0
dl_task_timer+0x127/0x2b0
? push_dl_task.part.31+0x190/0x190
As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/deadline.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index fcb7f0217ff4..1ce8867283dc 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -658,8 +658,11 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer) * * XXX figure out if select_task_rq_dl() deals with offline cpus. */ - if (unlikely(!rq->online)) + if (unlikely(!rq->online)) { + lockdep_unpin_lock(&rq->lock, rf.cookie); rq = dl_task_offline_migration(rq, p); + rf.cookie = lockdep_pin_lock(&rq->lock); + } /* * Queueing this task back might have overloaded rq, check if we need |