diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 5241102b81a82ad89f61fe7370e16fe226cfa285..a2d4eed27f804c0c51e4ea9b718387946e92fa6c 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3632,6 +3632,7 @@ static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
 		WARN_ON(1);
 		tsession = NULL;
 		target = -1;
+		mutex_lock(&session->s_mutex);
 	}
 	goto retry;