diff options
| author | Juri Lelli <juri.lelli@arm.com> | 2014-10-24 10:16:38 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-10-28 10:46:01 +0100 |
| commit | aee38ea95419c818dfdde52b115aeffe9cbb259b (patch) | |
| tree | 438cee90383ef1e33e33372f3a70b77a524a2e9b /kernel/sched/fair.c | |
| parent | 64be6f1f5f710f5995d41caf8a1767fe6d2b5a87 (diff) | |
sched/deadline: Fix races between rt_mutex_setprio() and dl_task_timer()
dl_task_timer() is racy against several paths. Daniel noticed that
the replenishment timer may experience a race condition against an
enqueue_dl_entity() called from rt_mutex_setprio(). With his own
words:
rt_mutex_setprio() resets p->dl.dl_throttled. So the pattern is:
start_dl_timer() throttled = 1, rt_mutex_setprio() throlled = 0,
sched_switch() -> enqueue_task(), dl_task_timer-> enqueue_task()
throttled is 0
=> BUG_ON(on_dl_rq(dl_se)) fires as the scheduling entity is already
enqueued on the -deadline runqueue.
As we do for the other races, we just bail out in the replenishment
timer code.
Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Tested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: vincent@legout.info
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Fabio Checconi <fchecconi@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1414142198-18552-5-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
0 files changed, 0 insertions, 0 deletions