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authorLinus Torvalds <torvalds@linux-foundation.org>2019-01-27 11:52:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-01-27 11:52:50 -0800
commit9881051828375a872964f91bf985b8a35e4fbaef (patch)
treea7e8a0503ecdb19bdcd5cf2bf5696143f2c4900b /include
parent0d484375d73ad2ec39a395365449a70c200645b1 (diff)
parente158488be27b157802753a59b336142dc0eb0380 (diff)
downloadlinux-9881051828375a872964f91bf985b8a35e4fbaef.tar.bz2
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner: "A small series of fixes which all address possible missed wakeups: - Document and fix the wakeup ordering of wake_q - Add the missing barrier in rcuwait_wake_up(), which was documented in the comment but missing in the code - Fix the possible missed wakeups in the rwsem and futex code" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/rwsem: Fix (possible) missed wakeup futex: Fix (possible) missed wakeup sched/wake_q: Fix wakeup ordering for wake_q sched/wake_q: Document wake_q_add() sched/wait: Fix rcuwait_wake_up() ordering
Diffstat (limited to 'include')
-rw-r--r--include/linux/sched/wake_q.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h
index 10b19a192b2d..545f37138057 100644
--- a/include/linux/sched/wake_q.h
+++ b/include/linux/sched/wake_q.h
@@ -24,9 +24,13 @@
* called near the end of a function. Otherwise, the list can be
* re-initialized for later re-use by wake_q_init().
*
- * Note that this can cause spurious wakeups. schedule() callers
+ * NOTE that this can cause spurious wakeups. schedule() callers
* must ensure the call is done inside a loop, confirming that the
* wakeup condition has in fact occurred.
+ *
+ * NOTE that there is no guarantee the wakeup will happen any later than the
+ * wake_q_add() location. Therefore task must be ready to be woken at the
+ * location of the wake_q_add().
*/
#include <linux/sched.h>