lib/btree: fix possible NULL pointer dereference

mempool_alloc() can return null in atomic case.

Signed-off-by: Denis Kirjanov <kirjanov@gmail.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/btree.c b/lib/btree.c
index 41859a820218..c9c6f0351526 100644
--- a/lib/btree.c
+++ b/lib/btree.c
@@ -95,7 +95,8 @@ static unsigned long *btree_node_alloc(struct btree_head *head, gfp_t gfp)
         unsigned long *node;
 
         node = mempool_alloc(head->mempool, gfp);
-        memset(node, 0, NODESIZE);
+        if (likely(node))
+                memset(node, 0, NODESIZE);
         return node;
 }