mount -t tmpfs -o mpol=: check nodes online

Randy Dunlap reports that a tmpfs, mounted with NUMA mpol= specifying an
offline node, crashes as soon as data is allocated upon it.  Now restrict it
to online nodes, where before it restricted to MAX_NUMNODES.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Tested-and-acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index e537317..b6aae2b 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -967,6 +967,8 @@ static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_
 		*nodelist++ = '\0';
 		if (nodelist_parse(nodelist, *policy_nodes))
 			goto out;
+		if (!nodes_subset(*policy_nodes, node_online_map))
+			goto out;
 	}
 	if (!strcmp(value, "default")) {
 		*policy = MPOL_DEFAULT;