[Xen-devel] [PATCH linux-2.6.18-xen] blkback: don't call vbd_size() if bd_disk is NULL

[Laszlo Ersek <lersek@xxxxxxxxxx>]

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

Signed-off-by: Laszlo Ersek<lersek@xxxxxxxxxx>
---
 drivers/xen/blkback/vbd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -r 415a9b435fef drivers/xen/blkback/vbd.c
--- a/drivers/xen/blkback/vbd.c Mon May 23 18:36:33 2011 +0100
+++ b/drivers/xen/blkback/vbd.c Wed May 25 12:15:26 2011 +0200
@@ -73,7 +73,6 @@ int vbd_create(blkif_t *blkif, blkif_vde
        }

        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_vde
                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)

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