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authorFrederic Weisbecker <fweisbec@gmail.com>2015-02-16 19:20:07 +0100
committerIngo Molnar <mingo@kernel.org>2015-02-18 14:27:38 +0100
commit06b1f8083d6ed379ec1207a96339f23e8f7abfcf (patch)
tree4a26cb052b35a5fa11e7d731d367b3e34bf5cdfa /kernel
parentsched/dl: Prevent enqueue of a sleeping task in dl_task_timer() (diff)
downloadlinux-dev-06b1f8083d6ed379ec1207a96339f23e8f7abfcf.tar.xz
linux-dev-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')
-rw-r--r--kernel/sched/core.c2
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);