[34-longterm 035/209] numa: fix slab_node(MPOL_BIND)

From: Paul Gortmaker
Date: Thu Apr 14 2011 - 13:50:16 EST

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

| This is a commit scheduled for the next v2.6.34 longterm release. |
| If you see a problem with using this for longterm, please comment.|

commit 800416f799e0723635ac2d720ad4449917a1481c upstream.

When a node contains only HighMem memory, slab_node(MPOL_BIND)
dereferences a NULL pointer.

[ This code seems to go back all the way to commit 19770b32609b: "mm:
filter based on a nodemask as well as a gfp_mask". Which was back in
April 2008, and it got merged into 2.6.26. - Linus ]

Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
mm/mempolicy.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 08f40a2..c7f53b12 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1509,7 +1509,7 @@ unsigned slab_node(struct mempolicy *policy)
(void)first_zones_zonelist(zonelist, highest_zoneidx,
- return zone->node;
+ return zone ? zone->node : numa_node_id();


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