dm mpath: always free attached_handler_name in parse_path()

commit 940bc471 upstream.

Commit b592211c ("dm mpath: fix attached_handler_name leak and
dangling hw_handler_name pointer") fixed a memory leak for the case
where setup_scsi_dh() returns failure. But setup_scsi_dh may return
success and not "use" attached_handler_name if the
retain_attached_hwhandler flag is not set on the map. As setup_scsi_sh
properly "steals" the pointer by nullifying it, freeing it
unconditionally in parse_path() is safe.

Fixes: b592211c ("dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer")
Cc: stable@vger.kernel.org
Reported-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/md/dm-mpath.c

@@ -882,6 +882,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
 	if (attached_handler_name || m->hw_handler_name) {
 		INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
 		r = setup_scsi_dh(p->path.dev->bdev, m, &attached_handler_name, &ti->error);
+		kfree(attached_handler_name);
 		if (r) {
 			dm_put_device(ti, p->path.dev);
 			goto bad;
@@ -896,7 +897,6 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
 
 	return p;
  bad:
-	kfree(attached_handler_name);
 	free_pgpath(p);
 	return ERR_PTR(r);
 }