cifs: cope with negative dentries in cifs_get_root
The loop around lookup_one_len doesn't handle the case where it might
return a negative dentry, which can cause an oops on the next pass
through the loop. Check for that and break out of the loop with an
error of -ENOENT if there is one.
Fixes the panic reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=727927
Reported-by: TR Bentley <home@trarbentley.net>
Reported-by: Iain Arnell <iarnell@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 212e562..f93eb94 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -563,6 +563,10 @@
mutex_unlock(&dir->i_mutex);
dput(dentry);
dentry = child;
+ if (!dentry->d_inode) {
+ dput(dentry);
+ dentry = ERR_PTR(-ENOENT);
+ }
} while (!IS_ERR(dentry));
_FreeXid(xid);
kfree(full_path);