From patchwork Fri Nov 13 21:49:21 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 544637 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 37571141452; Sat, 14 Nov 2015 08:58:28 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZxMMU-0000Sn-1K; Fri, 13 Nov 2015 21:58:26 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZxMEs-0004UX-T2 for kernel-team@lists.ubuntu.com; Fri, 13 Nov 2015 21:50:34 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ZxMEs-0007od-MV; Fri, 13 Nov 2015 21:50:34 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1ZxMEq-0004PJ-FH; Fri, 13 Nov 2015 13:50:32 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13.y-ckt 67/96] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) Date: Fri, 13 Nov 2015 13:49:21 -0800 Message-Id: <1447451390-16480-68-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1447451390-16480-1-git-send-email-kamal@canonical.com> References: <1447451390-16480-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Cc: Kamal Mostafa , Cathy Avery , Konrad Rzeszutek Wilk X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.13.11-ckt30 -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: Kamal Mostafa --- 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 fdee753..0035645e 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1917,7 +1917,8 @@ 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; } }