From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:35161 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbbKIL4o (ORCPT ); Mon, 9 Nov 2015 06:56:44 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: Cathy Avery , Konrad Rzeszutek Wilk , Jiri Slaby Subject: [patch added to the 3.12 stable tree] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) Date: Mon, 9 Nov 2015 12:56:30 +0100 Message-Id: <1447070198-11171-9-git-send-email-jslaby@suse.cz> In-Reply-To: <1447070198-11171-1-git-send-email-jslaby@suse.cz> References: <1447070198-11171-1-git-send-email-jslaby@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: From: Cathy Avery This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== 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 Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Jiri Slaby --- drivers/block/xen-blkfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 7d0eb3f8d629..0b6932c376fb 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1965,7 +1965,8 @@ static void blkback_changed(struct xenbus_device *dev, break; /* Missed the backend's Closing state -- fallthrough */ case XenbusStateClosing: - blkfront_closing(info); + if (info) + blkfront_closing(info); break; } } -- 2.6.3