The patch titled
tmpfs: fix oops on mounts with mpol=default
has been added to the -mm tree. Its filename is
tmpfs-fix-oops-on-mounts-with-mpol=default.patch
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------------------------------------------------------
Subject: tmpfs: fix oops on mounts with mpol=default
From: Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Acked-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN mm/mempolicy.c~tmpfs-fix-oops-on-mounts-with-mpol=default mm/mempolicy.c
--- a/mm/mempolicy.c~tmpfs-fix-oops-on-mounts-with-mpol=default
+++ a/mm/mempolicy.c
@@ -2215,10 +2215,15 @@ 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.
*/
}
_
Patches currently in -mm which might be from kiran@xxxxxxxxxxxx are
tmpfs-fix-oops-on-mounts-with-mpol=default.patch
tmpfs-mpol=bind-0-dont-cause-mount-error.patch
tmpfs-handle-mpol_local-mount-option-properly.patch
tmpfs-cleanup-mpol_parse_str.patch
doc-add-the-documentation-for-mpol=local.patch
slab-leaks3-default-y.patch
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