diff options
| author | Oleg Nesterov <[email protected]> | 2015-07-21 15:40:36 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2015-07-31 10:38:07 +0200 |
| commit | 2a742cedcf13572999436676cbe36c3a9b733b0f (patch) | |
| tree | bb614fd0d0204a48f9ff739bced7cb45567f9fdb | |
| parent | 704bde3cc26a4cb34386c164107b59e09745a022 (diff) | |
uprobes: Fix the waitqueue_active() check in xol_free_insn_slot()
The xol_free_insn_slot()->waitqueue_active() check is buggy. We
need mb() after we set the conditon for wait_event(), or
xol_take_insn_slot() can miss the wakeup.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Pratyush Anand <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | kernel/events/uprobes.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 2d5b7bd337a7..4e5e9798aa0c 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1337,6 +1337,7 @@ static void xol_free_insn_slot(struct task_struct *tsk) clear_bit(slot_nr, area->bitmap); atomic_dec(&area->slot_count); + smp_mb__after_atomic(); /* pairs with prepare_to_wait() */ if (waitqueue_active(&area->wq)) wake_up(&area->wq); |