From: Laszlo Ersek <lersek@redhat.com>
Date: Thu, 26 May 2011 07:09:04 +0000 (+0100)
Subject: blkback: don't call vbd_size() if bd_disk is NULL
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=c8efeb775811e952e17b837d4bc655377221ea01;p=legacy%2Flinux-2.6.18-xen.git

blkback: don't call vbd_size() if bd_disk is NULL

...because vbd_size() dereferences bd_disk if bd_part is NULL.

Signed-off-by: Laszlo Ersek<lersek@redhat.com>
Acked-by: Jan Beulich <jbeulich@novell.com>
---

diff --git a/drivers/xen/blkback/vbd.c b/drivers/xen/blkback/vbd.c
index 5677e86c..8d5d9a14 100644
--- a/drivers/xen/blkback/vbd.c
+++ b/drivers/xen/blkback/vbd.c
@@ -73,7 +73,6 @@ int vbd_create(blkif_t *blkif, blkif_vdev_t handle, unsigned major,
 	}
 
 	vbd->bdev = bdev;
-	vbd->size = vbd_size(vbd);
 
 	if (vbd->bdev->bd_disk == NULL) {
 		DPRINTK("vbd_creat: device %08x doesn't exist.\n",
@@ -82,6 +81,8 @@ int vbd_create(blkif_t *blkif, blkif_vdev_t handle, unsigned major,
 		return -ENOENT;
 	}
 
+	vbd->size = vbd_size(vbd);
+
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
 		vbd->type |= VDISK_CDROM;
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)