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@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> Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx> Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> --- 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>