From 26e6ab3e52ef3f4399bb7e94eb71c553cace88fe Mon Sep 17 00:00:00 2001
From: Cathy Avery <cathy.avery@oracle.com>
Date: Fri, 2 Oct 2015 09:35:01 -0400
Subject: [PATCH] xen-blkfront: check for null drvdata in blkback_changed
 (XenbusStateClosing)

commit a54c8f0f2d7df525ff997e2afe71866a1a013064 upstream.

xen-blkfront will crash if the check to talk_to_blkback()
in blkback_changed()(XenbusStateInitWait) returns an error.
The driver data is freed and info is set to NULL. Later during
the close process via talk_to_blkback's call to xenbus_dev_fatal()
the null pointer is passed to and dereference in blkfront_closing.

Signed-off-by: Cathy Avery <cathy.avery@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
Reading git-format-patch failed