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authorPeter Zijlstra <peterz@infradead.org>2014-09-24 10:18:46 +0200
committerIngo Molnar <mingo@kernel.org>2014-10-28 10:55:08 +0100
commit6f942a1f264e875c5f3ad6f505d7b500a3e7fa82 (patch)
tree261e52ac048e38cba572b08c9707c36b7bbecc5f /kernel/locking
parentf4e9d94a5bf60193d45f92b136e3d166be3ec8d5 (diff)
locking/mutex: Don't assume TASK_RUNNING
We're going to make might_sleep() test for TASK_RUNNING, because blocking without TASK_RUNNING will destroy the task state by setting it to TASK_RUNNING. There are a few occasions where its 'valid' to call blocking primitives (and mutex_lock in particular) and not have TASK_RUNNING, typically such cases are right before we set TASK_RUNNING anyhow. Robustify the code by not assuming this; this has the beneficial side effect of allowing optional code emission for fixing the above might_sleep() false positives. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: tglx@linutronix.de Cc: ilya.dryomov@inktank.com Cc: umgwanakikbuti@gmail.com Cc: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140924082241.988560063@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/mutex.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index dadbf88c22c4..454195194d4a 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -378,8 +378,14 @@ done:
* reschedule now, before we try-lock the mutex. This avoids getting
* scheduled out right after we obtained the mutex.
*/
- if (need_resched())
+ if (need_resched()) {
+ /*
+ * We _should_ have TASK_RUNNING here, but just in case
+ * we do not, make it so, otherwise we might get stuck.
+ */
+ __set_current_state(TASK_RUNNING);
schedule_preempt_disabled();
+ }
return false;
}