Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932919AbbKMKMK (ORCPT ); Fri, 13 Nov 2015 05:12:10 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:48868 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932448AbbKMKME (ORCPT ); Fri, 13 Nov 2015 05:12:04 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Cathy Avery , Konrad Rzeszutek Wilk , Luis Henriques Subject: [PATCH 3.16.y-ckt 47/94] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) Date: Fri, 13 Nov 2015 10:09:41 +0000 Message-Id: <1447409428-12178-48-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> References: <1447409428-12178-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1479 Lines: 40 3.16.7-ckt20 -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: Luis Henriques --- 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 2a29cf69cd73..1b683dbc3f88 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1905,7 +1905,8 @@ 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; } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/