From 25671cd0d574bba616ecf957b39e1f1029403d42 Mon Sep 17 00:00:00 2001
From: mckusick <mckusick@FreeBSD.org>
Date: Thu, 3 Dec 2015 02:04:22 +0000
Subject: [PATCH] We need to zero out the union of pointers in a freed vnode
 structure.

PR:        204949
Fix from:  Mateusz Guzik
Tested by: Jason Unovitch
---
 sys/kern/vfs_subr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index ddab9f046c46..ff37de832118 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -2782,6 +2782,7 @@ _vdrop(struct vnode *vp, bool locked)
 	/* XXX Elsewhere we detect an already freed vnode via NULL v_op. */
 	vp->v_op = NULL;
 #endif
+	bzero(&vp->v_un, sizeof(vp->v_un));
 	vp->v_iflag = 0;
 	vp->v_vflag = 0;
 	bo->bo_flag = 0;