From a4fcac54a171f9b11bd2ba6d4ca64834b32e2bff Mon Sep 17 00:00:00 2001
From: Bruce Evans <bde@FreeBSD.org>
Date: Thu, 9 Mar 2000 12:40:41 +0000
Subject: [PATCH] Fixed a null pointer panic for dumpon(8) on a nonexistent
 device whose driver uses the new disk layer.

Reviewed by:	phk
Approved by:	jkh
---
 sys/kern/subr_disk.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
index cf1b3ccab8cf..23ec0034988d 100644
--- a/sys/kern/subr_disk.c
+++ b/sys/kern/subr_disk.c
@@ -229,6 +229,8 @@ diskpsize(dev_t dev)
 	if (!dp) {
 		pdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
 		dp = pdev->si_disk;
+		if (!dp)
+			return (-1);
 		dev->si_drv1 = pdev->si_drv1;
 		dev->si_drv2 = pdev->si_drv2;
 		/* XXX: don't set bp->b_dev->si_disk (?) */