From 3ca30d40a91fb9b9871e61d5dea2c1a895906a15 Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky Date: Mon, 25 Jul 2011 17:59:10 +0400 Subject: [PATCH] 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 Signed-off-by: Al Viro --- fs/cifs/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 14d602f178c2..499f27fc8576 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -641,7 +641,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, static int cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd) { - if (nd->flags & LOOKUP_RCU) + if (nd && (nd->flags & LOOKUP_RCU)) return -ECHILD; if (direntry->d_inode) {