From 09a2776e693b4dac1f7a62f8e264ecf07bb78485 Mon Sep 17 00:00:00 2001
From: marcus <marcus@FreeBSD.org>
Date: Tue, 23 Dec 2008 20:43:42 +0000
Subject: [PATCH] Do not KASSERT when vp->v_dd is NULL.  Only directories which
 have had ".." looked up would have v_dd set to a non-NULL value.  This fixes
 a panic seen when running installworld on a diskless system with a separate
 /usr file system.

Submitted by:	cracauer
Approved by:	kib
---
 sys/kern/vfs_cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index d3829c99ff35..6fad06e1f498 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -936,7 +936,7 @@ vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
 		}
 		ncp = TAILQ_FIRST(&vp->v_cache_dst);
 		if (ncp != NULL) {
-			MPASS(ncp->nc_dvp == vp->v_dd);
+			MPASS(vp->v_dd == NULL || ncp->nc_dvp == vp->v_dd);
 			buflen -= ncp->nc_nlen - 1;
 			for (i = ncp->nc_nlen - 1; i >= 0 && bp != buf; i--)
 				*--bp = ncp->nc_name[i];