From: Laszlo Ersek <lersek@redhat.com>
Date: Wed, 25 May 2011 10:24:25 +0000 (+0200)
Subject: xen/blkback: don't call vbd_size() if bd_disk is NULL
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6464920a6e30604cb71d0ecbaa20e35009bd76fb;p=linux-beck.git

xen/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>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 34570823355b..6cc0db1bf522 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -357,14 +357,13 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	}
 
 	vbd->bdev = bdev;
-	vbd->size = vbd_sz(vbd);
-
 	if (vbd->bdev->bd_disk == NULL) {
 		DPRINTK("xen_vbd_create: device %08x doesn't exist.\n",
 			vbd->pdevice);
 		xen_vbd_free(vbd);
 		return -ENOENT;
 	}
+	vbd->size = vbd_sz(vbd);
 
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
 		vbd->type |= VDISK_CDROM;