[PATCH] SGI-PV: Read buffer overflow

[Roel Kluin <roel.kluin@xxxxxxxxx>]

Check whether index is within bounds before grabbing the element.

Signed-off-by: Roel Kluin <roel.kluin@xxxxxxxxx>
---
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);