From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id BB41E6001DA for ; Tue, 16 Mar 2010 01:49:33 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o2G5nUbL028836 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 16 Mar 2010 14:49:30 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 2B6AC45DE55 for ; Tue, 16 Mar 2010 14:49:30 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 0464B45DE51 for ; Tue, 16 Mar 2010 14:49:30 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id D6D291DB803E for ; Tue, 16 Mar 2010 14:49:29 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 853511DB8038 for ; Tue, 16 Mar 2010 14:49:29 +0900 (JST) From: KOSAKI Motohiro Subject: [PATCH 1/5] tmpfs: fix oops on mounts with mpol=default In-Reply-To: <20100316143406.4C45.A69D9226@jp.fujitsu.com> References: <201003122353.o2CNrC56015250@imap1.linux-foundation.org> <20100316143406.4C45.A69D9226@jp.fujitsu.com> Message-Id: <20100316144810.4C48.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 16 Mar 2010 14:49:28 +0900 (JST) Sender: owner-linux-mm@kvack.org To: LKML Cc: kosaki.motohiro@jp.fujitsu.com, kiran@scalex86.org, cl@linux-foundation.org, hugh.dickins@tiscali.co.uk, lee.schermerhorn@hp.com, mel@csn.ul.ie, stable@kernel.org, linux-mm , akpm@linux-foundation.org List-ID: ChangeLog from Ravikiran's original one - Fix the patch description. the problem is in mount, not only remount. - Skip mpol_new() simply, instead adding NULL check. ========================= From: Ravikiran G Thirumalai Fix an 'oops' when a tmpfs mount point is mounted with the mpol=default mempolicy. Upon remounting a tmpfs mount point with 'mpol=default' option, the mount code crashed with a null pointer dereference. The initial problem report was on 2.6.27, but the problem exists in mainline 2.6.34-rc as well. On examining the code, we see that mpol_new returns NULL if default mempolicy was requested. This 'NULL' mempolicy is accessed to store the node mask resulting in oops. The following patch fixes it. Signed-off-by: Ravikiran Thirumalai Signed-off-by: KOSAKI Motohiro Cc: Christoph Lameter Cc: Mel Gorman Cc: Lee Schermerhorn Cc: Hugh Dickins Cc: --- mm/mempolicy.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index bda230e..25a0c0f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2213,10 +2213,15 @@ int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context) goto out; mode = MPOL_PREFERRED; break; - + case MPOL_DEFAULT: + /* + * Insist on a empty nodelist + */ + if (!nodelist) + err = 0; + goto out; /* * case MPOL_BIND: mpol_new() enforces non-empty nodemask. - * case MPOL_DEFAULT: mpol_new() enforces empty nodemask, ignores flags. */ } -- 1.6.5.2 -- 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