diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 52937c923931..190480095d4a 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -1714,6 +1714,9 @@ vfs_getopt(opts, name, buf, len)
 {
 	struct vfsopt *opt;
 
+	KASSERT(opts != NULL,
+	    ("vfs_getopt: caller passed 'opts' as NULL\n"));
+
 	TAILQ_FOREACH(opt, opts, link) {
 		if (strcmp(name, opt->name) == 0) {
 			if (len != NULL)
@@ -1743,6 +1746,9 @@ vfs_copyopt(opts, name, dest, len)
 {
 	struct vfsopt *opt;
 
+	KASSERT(opts != NULL,
+	    ("vfs_copyopt: caller passed 'opts' as NULL\n"));
+
 	TAILQ_FOREACH(opt, opts, link) {
 		if (strcmp(name, opt->name) == 0) {
 			if (len != opt->len)