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authorOleg Nesterov <oleg@tv-sign.ru>2007-05-09 02:34:20 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 12:30:53 -0700
commit85f4186af944c1240c84934a9ab578743df2d69b (patch)
tree743d6a619538cda98495aaaac67a86246d3007e4
parentb9aac8e0d32499217417ff0b494731811f185b18 (diff)
worker_thread: fix racy try_to_freeze() usage
worker_thread() can miss freeze_process()->signal_wake_up() if it happens between try_to_freeze() and prepare_to_wait(). We should check freezing() before entering schedule(). This race was introduced by me in [PATCH 1/1] workqueue: don't migrate pending works from the dead CPU Looks like mm/vmscan.c:kswapd() has the same race. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/workqueue.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 87693b37d01..63885abf1ba 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -308,14 +308,14 @@ static int worker_thread(void *__cwq)
do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
for (;;) {
- if (cwq->wq->freezeable)
- try_to_freeze();
-
prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
- if (!cwq->should_stop && list_empty(&cwq->worklist))
+ if (!freezing(current) && !cwq->should_stop
+ && list_empty(&cwq->worklist))
schedule();
finish_wait(&cwq->more_work, &wait);
+ try_to_freeze();
+
if (cwq_should_stop(cwq))
break;