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authorRavikiran G Thirumalai <kiran@scalex86.org>2010-03-23 13:35:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-24 16:31:21 -0700
commit413b43deab8377819aba1dbad2abf0c15d59b491 (patch)
tree07ed7302b20b620f09c479e36c6fd7bd02559860 /mm
parent8c363afe94b885d39ae2e93e41680282a470ad84 (diff)
downloadconfigs-413b43deab8377819aba1dbad2abf0c15d59b491.tar.gz
tmpfs: fix oops on mounts with mpol=default
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> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mempolicy.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 643f66e1018..745ce90308a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2215,10 +2215,15 @@ 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.
*/
}