tree 8c65823f6076c2bf25e11f5756abe704deca7708
parent e010a5ef95b8b6a12b74b548578f7dcf93564347
author Pavel Shilovsky <piastryyy@gmail.com> 1311602350 +0400
committer Steve French <sfrench@us.ibm.com> 1311631600 +0000

CIFS: Fix oops while mounting with prefixpath

commit fec11dd9a0109fe52fd631e5c510778d6cbff6cc caused
a regression when we have already mounted //server/share/a
and want to mount //server/share/a/b.

The problem is that lookup_one_len calls __lookup_hash
with nd pointer as NULL. Then __lookup_hash calls
do_revalidate in the case when dentry exists and we end
up with NULL pointer deference in cifs_d_revalidate:

if (nd->flags & LOOKUP_RCU)
	return -ECHILD;

Fix this by checking nd for NULL.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Shirish Pargaonkar <shirishp@us.ibm.com>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>