[PATCH] SGI-PV: Read buffer overflow

[Roel Kluin]

Check whether index is within bounds before grabbing the element.

Signed-off-by: Roel Kluin <roel.kluin at gmail.com>
---
diff --git a/fs/xfs/xfs_da_btree.c b/fs/xfs/xfs_da_btree.c
index 9ff6e57..ef1d275 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -1414,8 +1414,9 @@ xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
 	ASSERT(args != NULL);
 	ASSERT(path != NULL);
 	ASSERT((path->active > 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
-	level = (path->active-1) - 1;	/* skip bottom layer in path */
-	for (blk = &path->blk[level]; level >= 0; blk--, level--) {
+	/* skip bottom layer in path */
+	for (level = (path->active-1) - 1; level >= 0; blk--, level--) {
+		blk = &path->blk[level];
 		ASSERT(blk->bp != NULL);
 		node = blk->bp->data;
 		ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);