The patch titled
tmpfs: fix oops on remounts with mpol=default
has been removed from the -mm tree. Its filename was
tmpfs-fix-oops-on-remounts-with-mpol=default.patch
This patch was dropped because an updated version will be merged
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: tmpfs: fix oops on remounts with mpol=default
From: Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx>
Fix an 'oops' when a tmpfs mount point is remounted with the 'default'
mempolicy.
Upon remounting a tmpfs mount point with 'mpol=default' option, the
remount 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 the oops by avoiding dereferencing NULL if the
new mempolicy is NULL. The patch also sets 'err' to 0 if MPOL_DEFAULT is
passed (err is initialized to 1 initially at mpol_parse_str())
Signed-off-by: Ravikiran Thirumalai <kiran@xxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff -puN mm/mempolicy.c~tmpfs-fix-oops-on-remounts-with-mpol=default mm/mempolicy.c
--- a/mm/mempolicy.c~tmpfs-fix-oops-on-remounts-with-mpol=default
+++ a/mm/mempolicy.c
@@ -2213,10 +2213,14 @@ int mpol_parse_str(char *str, struct mem
goto out;
mode = MPOL_PREFERRED;
break;
-
+ case MPOL_DEFAULT:
+ /*
+ * mpol_new() enforces empty nodemask, ignores flags.
+ */
+ err = 0;
+ break;
/*
* case MPOL_BIND: mpol_new() enforces non-empty nodemask.
- * case MPOL_DEFAULT: mpol_new() enforces empty nodemask, ignores flags.
*/
}
@@ -2250,7 +2254,7 @@ int mpol_parse_str(char *str, struct mem
if (ret) {
err = 1;
mpol_put(new);
- } else if (no_context) {
+ } else if (no_context && new) {
/* save for contextualization */
new->w.user_nodemask = nodes;
}
_
Patches currently in -mm which might be from kiran@xxxxxxxxxxxx are
tmpfs-fix-oops-on-remounts-with-mpol=default.patch
slab-leaks3-default-y.patch
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