From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031688AbbKFTmL (ORCPT ); Fri, 6 Nov 2015 14:42:11 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:48079 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032971AbbKFTmC (ORCPT ); Fri, 6 Nov 2015 14:42:02 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cathy Avery , Konrad Rzeszutek Wilk Subject: [PATCH 3.14 26/37] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) Date: Fri, 6 Nov 2015 11:24:41 -0800 Message-Id: <20151106192412.387618287@linuxfoundation.org> X-Mailer: git-send-email 2.6.2 In-Reply-To: <20151106192410.681850286@linuxfoundation.org> References: <20151106192410.681850286@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cathy Avery 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: Greg Kroah-Hartman --- drivers/block/xen-blkfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1917,7 +1917,8 @@ static void blkback_changed(struct xenbu break; /* Missed the backend's Closing state -- fallthrough */ case XenbusStateClosing: - blkfront_closing(info); + if (info) + blkfront_closing(info); break; } }