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| author | Ravikiran G Thirumalai <kiran@scalex86.org> | 2010-03-23 13:35:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-24 16:31:21 -0700 |
| commit | 413b43deab8377819aba1dbad2abf0c15d59b491 (patch) | |
| tree | 07ed7302b20b620f09c479e36c6fd7bd02559860 | |
| parent | 8c363afe94b885d39ae2e93e41680282a470ad84 (diff) | |
| download | linux-3.10-413b43deab8377819aba1dbad2abf0c15d59b491.tar.gz linux-3.10-413b43deab8377819aba1dbad2abf0c15d59b491.tar.bz2 linux-3.10-413b43deab8377819aba1dbad2abf0c15d59b491.zip | |
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>
| -rw-r--r-- | mm/mempolicy.c | 9 |
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. */ } |