From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Date: Thu, 3 Dec 2009 12:49:43 +0000 (+0100)
Subject: flusher: Fix PF_FROZEN race
X-Git-Tag: v2.6.33-rc1~379^2~37
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bf7ec5bb6114b2f086e536e24486fdacd1c0d339;p=platform%2Fkernel%2Flinux-exynos.git

flusher: Fix PF_FROZEN race

To touch task->flags directly is racy. thaw_process() still has race
(changing non_current->flags, but this is another issue) though, I think
it's much better off.

So, use thaw_process() instead.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 67a33a5..0e8ca03 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -609,7 +609,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
 	 * it would never exet if it is currently stuck in the refrigerator.
 	 */
 	list_for_each_entry(wb, &bdi->wb_list, list) {
-		wb->task->flags &= ~PF_FROZEN;
+		thaw_process(wb->task);
 		kthread_stop(wb->task);
 	}
 }