Index: sys/kern/vfs_syscalls.c
===================================================================
--- sys/kern/vfs_syscalls.c
+++ sys/kern/vfs_syscalls.c
@@ -480,10 +480,14 @@
 			continue;
 		}
 #endif
-		if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
+		vfs_ref(mp);
+		if (vfs_busy(mp, (flags == MNT_WAIT ? 0 : MBF_NOWAIT) |
+		    MBF_MNTLSTLOCK)) {
 			nmp = TAILQ_NEXT(mp, mnt_list);
+			vfs_rel(mp);
 			continue;
 		}
+		vfs_rel(mp);
 		if (sfsp && count < maxcount) {
 			sp = &mp->mnt_stat;
 			/*