[PATCH] reiserfs: UBSAN: array-index-out-of-bounds in direntry_create_vi

deh defined as an array of type __u16[], and issue is
triggered when it's trying to access an element at
index 1, which is out of bounds because the array
has only one element at index 0.

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=e5bb9eb00a5a5ed2a9a2
Signed-off-by: Bragatheswaran Manickavel <[email protected]>
---
 fs/reiserfs/item_ops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/reiserfs/item_ops.c b/fs/reiserfs/item_ops.c
index 3a5a752d96c7..ccf547c5e8e1 100644
--- a/fs/reiserfs/item_ops.c
+++ b/fs/reiserfs/item_ops.c
@@ -484,7 +484,7 @@ static int direntry_create_vi(struct virtual_node *vn,
 				  vn->vn_mode);
 		dir_u->entry_sizes[i] =
 		    (j ? deh_location(&deh[j - 1]) : ih_item_len(vi->vi_ih)) -
-		    deh_location(&deh[j]) + DEH_SIZE;
+		    deh_location(&deh[j - 1]) + DEH_SIZE;
 	}
 
 	size += (dir_u->entry_count * sizeof(short));
-- 
2.34.1