Commit 8b6c5845 authored by Ronnie Sahlberg's avatar Ronnie Sahlberg Committed by Steve French
Browse files

cifs: verify that tcon is valid before dereference in cifs_kill_sb 



On umount, cifs_sb->tlink_tree might contain entries that do not represent
a valid tcon.
Check the tcon for error before we dereference it.

Signed-off-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarShyam Prasad N <sprasad@microsoft.com>
Reported-by: default avatarXiaoli Feng <xifeng@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 64c4a37a

fs/cifs/cifsfs.c

+3 −3
Original line number Diff line number Diff line
@@ -266,10 +266,11 @@ static void cifs_kill_sb(struct super_block *sb) 
	 * before we kill the sb.

	 */

	if (cifs_sb->root) {

		node = rb_first(root);

		while (node != NULL) {

		for (node = rb_first(root); node; node = rb_next(node)) {

			tlink = rb_entry(node, struct tcon_link, tl_rbnode);

			tcon = tlink_tcon(tlink);

			if (IS_ERR(tcon))

				continue;

			cfid = &tcon->crfid;

			mutex_lock(&cfid->fid_mutex);

			if (cfid->dentry) {
@@ -277,7 +278,6 @@ static void cifs_kill_sb(struct super_block *sb) 
				cfid->dentry = NULL;

			}

			mutex_unlock(&cfid->fid_mutex);

			node = rb_next(node);

		}



		/* finally release root dentry */