Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | [PATCH 1/5] tmpfs: fix oops on mounts with mpol=default | Date | Tue, 16 Mar 2010 14:49:28 +0900 (JST) |
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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 <kiran@scalex86.org>
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> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: <stable@kernel.org> --- 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
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