lkml.org 
[lkml]   [2010]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[052/116] tmpfs: fix oops on mounts with mpol=default
2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Ravikiran G Thirumalai <kiran@scalex86.org>

commit 413b43deab8377819aba1dbad2abf0c15d59b491 upstream.

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 <kiran@scalex86.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
mm/mempolicy.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2142,10 +2142,15 @@ int mpol_parse_str(char *str, struct mem
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.
*/
}




\
 
 \ /
  Last update: 2010-03-31 02:09    [W:0.774 / U:0.224 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site