[RFC][PATCH 2/7] Freezer: Fix memory ordering in refrigerator

From: Rafael J. Wysocki
Date: Fri Feb 23 2007 - 06:55:29 EST


From: Oleg Nesterov <oleg@xxxxxxxxxx>

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

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
kernel/power/process.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

Index: linux-2.6.20-mm2/kernel/power/process.c
===================================================================
--- linux-2.6.20-mm2.orig/kernel/power/process.c
+++ linux-2.6.20-mm2/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);

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/