diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
index 125c5bb64120..ba7c654d4f0a 100644
--- a/sys/fs/tmpfs/tmpfs_vfsops.c
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -544,8 +544,9 @@ tmpfs_unmount(struct mount *mp, int mntflags)
 void
 tmpfs_free_tmp(struct tmpfs_mount *tmp)
 {
-
+	TMPFS_MP_ASSERT_LOCKED(tmp);
 	MPASS(tmp->tm_refcount > 0);
+
 	tmp->tm_refcount--;
 	if (tmp->tm_refcount > 0) {
 		TMPFS_UNLOCK(tmp);