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author | 2015-02-16 19:20:07 +0100 | |
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committer | 2015-02-18 14:27:38 +0100 | |
commit | 06b1f8083d6ed379ec1207a96339f23e8f7abfcf (patch) | |
tree | 4a26cb052b35a5fa11e7d731d367b3e34bf5cdfa /kernel/sched | |
parent | sched/dl: Prevent enqueue of a sleeping task in dl_task_timer() (diff) | |
download | linux-06b1f8083d6ed379ec1207a96339f23e8f7abfcf.tar.gz linux-06b1f8083d6ed379ec1207a96339f23e8f7abfcf.tar.bz2 linux-06b1f8083d6ed379ec1207a96339f23e8f7abfcf.zip |
sched: Fix preempt_schedule_common() triggering tracing recursion
Since the function graph tracer needs to disable preemption, it might
call preempt_schedule() after reenabling it if something triggered the
need for rescheduling in between.
Therefore we can't trace preempt_schedule() itself because we would
face a function tracing recursion otherwise as the tracer is always
called before PREEMPT_ACTIVE gets set to prevent that recursion. This is
why preempt_schedule() is tagged as "notrace".
But the same issue applies to every function called by preempt_schedule()
before PREEMPT_ACTIVE is actually set. And preempt_schedule_common() is
one such example. Unfortunately we forgot to tag it as notrace as well
and as a result we are encountering tracing recursion since it got
introduced by:
a18b5d0181923 ("sched: Fix missing preemption opportunity")
Let's fix that by applying the appropriate function tag to
preempt_schedule_common().
Reported-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1424110807-15057-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f77acd98f50a..c314000f5e52 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2839,7 +2839,7 @@ void __sched schedule_preempt_disabled(void) preempt_disable(); } -static void preempt_schedule_common(void) +static void __sched notrace preempt_schedule_common(void) { do { __preempt_count_add(PREEMPT_ACTIVE); |