From 4eabcb748c606ee33da37c5d874efb29a18f859a Mon Sep 17 00:00:00 2001 From: "kaf24@firebug.cl.cam.ac.uk" Date: Tue, 16 May 2006 09:40:38 +0100 Subject: [PATCH] Prevent an oops in Dom0 that occurs when a CD device, specified as one of the 'hardrives' in the 'disk=' line of a para-virtualized guest's def file, has no media when the guest is started. The oops occurs in vbd.c when vbd_size() is called from connect() (in xenbus.c) and the vbd pointer is really an error code that comes from the failed open that occurred in vbd_create(). Based on a patch from Ross Maxfield at Novell. Signed-off-by: Keir Fraser --- linux-2.6-xen-sparse/drivers/xen/blkback/vbd.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/linux-2.6-xen-sparse/drivers/xen/blkback/vbd.c b/linux-2.6-xen-sparse/drivers/xen/blkback/vbd.c index d1d38dcd76..3c4a3b13a3 100644 --- a/linux-2.6-xen-sparse/drivers/xen/blkback/vbd.c +++ b/linux-2.6-xen-sparse/drivers/xen/blkback/vbd.c @@ -55,6 +55,7 @@ int vbd_create(blkif_t *blkif, blkif_vdev_t handle, unsigned major, unsigned minor, int readonly) { struct vbd *vbd; + struct block_device *bdev; vbd = &blkif->vbd; vbd->handle = handle; @@ -63,15 +64,17 @@ int vbd_create(blkif_t *blkif, blkif_vdev_t handle, unsigned major, vbd->pdevice = MKDEV(major, minor); - vbd->bdev = open_by_devnum( - vbd->pdevice, - vbd->readonly ? FMODE_READ : FMODE_WRITE); - if (IS_ERR(vbd->bdev)) { - DPRINTK("vbd_creat: device %08x doesn't exist.\n", + bdev = open_by_devnum(vbd->pdevice, + vbd->readonly ? FMODE_READ : FMODE_WRITE); + + if (IS_ERR(bdev)) { + DPRINTK("vbd_creat: device %08x could not be opened.\n", vbd->pdevice); return -ENOENT; } + vbd->bdev = bdev; + if (vbd->bdev->bd_disk == NULL) { DPRINTK("vbd_creat: device %08x doesn't exist.\n", vbd->pdevice); -- 2.30.2