[PATCH] fix refrigerator() vs thaw_process() race

From: Oleg Nesterov
Date: Sun Feb 18 2007 - 17:20:44 EST


refrigerator() can miss a wakeup, "wait event" loop needs a proper memory
ordering.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

--- WQ/kernel/power/process.c~WAKE 2007-02-18 22:56:49.000000000 +0300
+++ WQ/kernel/power/process.c 2007-02-19 01:04:26.000000000 +0300
@@ -46,8 +46,10 @@ void refrigerator(void)
recalc_sigpending(); /* We sent fake signal, clean it up */
spin_unlock_irq(&current->sighand->siglock);

- while (frozen(current)) {
- current->state = TASK_UNINTERRUPTIBLE;
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!frozen(current))
+ break;
schedule();
}
pr_debug("%s left refrigerator\n", current->comm);

-
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