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Fix kernel NULL pointer dereference in xen-blkfront

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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.
This commit is contained in:
Kris Shannon 2009-03-02 19:47:37 +11:00 committed by Jens Axboe
parent 559595a985
commit a1a15ac5f9
1 changed files with 2 additions and 0 deletions
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2
drivers/block/xen-blkfront.c
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@ -977,6 +977,8 @@ static void backend_changed(struct xenbus_device *dev,
break; break;
case XenbusStateClosing: case XenbusStateClosing:
if (info->gd == NULL)
xenbus_dev_fatal(dev, -ENODEV, "gd is NULL");
bd = bdget_disk(info->gd, 0); bd = bdget_disk(info->gd, 0);
if (bd == NULL) if (bd == NULL)
xenbus_dev_fatal(dev, -ENODEV, "bdget failed"); xenbus_dev_fatal(dev, -ENODEV, "bdget failed");