From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Sun, 6 May 2007 21:50:40 +0000 (-0700)
Subject: fix refrigerator() vs thaw_process() race
X-Git-Tag: v2.6.22-rc1~906
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=433ecb4ab312f873870b67ee374502e84f6dcf92;p=linux-2.6

fix refrigerator() vs thaw_process() race

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

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 6d566bf708..0eb5c420e8 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -47,8 +47,10 @@ 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);