Commit a1a15ac5 authored Mar 02, 2009 by Kris Shannon Committed by Jens Axboe Mar 05, 2009

Fix kernel NULL pointer dereference in xen-blkfront

When booting Xen Dom0 on a pre-release 3.2.1 hypervisor the system Oopses on a
"Unable to handle kernel NULL pointer dereference" in xenwatch.

From the backtrace it looks like backend_changed is calling bdget_disk
with a NULL pointer. Checking for NULL and returning ENODEV instead
allows the kernel to boot.

parent 559595a9

drivers/block/xen-blkfront.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -977,6 +977,8 @@ static void backend_changed(struct xenbus_device *dev,
		break;

		case XenbusStateClosing:
		if (info->gd == NULL)
		xenbus_dev_fatal(dev, -ENODEV, "gd is NULL");
		bd = bdget_disk(info->gd, 0);
		if (bd == NULL)
		xenbus_dev_fatal(dev, -ENODEV, "bdget failed");