From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 06 May 2008 14:40:39 +0900 From: KOSAKI Motohiro Subject: on CONFIG_MM_OWNER=y, kernel panic is possible. Message-Id: <20080506142255.AC5D.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Lee Schermerhorn , KAMEZAWA Hiroyuki , Balbir Singh , LKML , linux-mm , Andrew Morton Cc: kosaki.motohiro@jp.fujitsu.com List-ID: on CONFIG_MM_OWNER=y (that is automatically turned on by mem-cgroup), kernel panic is possible by following scenario in mm_update_next_owner(). 1. mm_update_next_owner() is called. 2. found caller task in do_each_thread() loop. 3. thus, BUG_ON(c == p) is true, it become kernel panic. end up, We should left out current task. Signed-off-by: KOSAKI Motohiro CC: Lee Schermerhorn CC: KAMEZAWA Hiroyuki CC: Balbir Singh --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: b/kernel/exit.c =================================================================== --- a/kernel/exit.c 2008-05-04 22:57:23.000000000 +0900 +++ b/kernel/exit.c 2008-05-06 15:01:26.000000000 +0900 @@ -627,7 +627,7 @@ retry: * here often */ do_each_thread(g, c) { - if (c->mm == mm) + if ((c != p) && (c->mm == mm)) goto assign_new_owner; } while_each_thread(g, c); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org