From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A76D1C2BC61 for ; Tue, 30 Oct 2018 16:48:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F99A20664 for ; Tue, 30 Oct 2018 16:48:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Q0uZbiyR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F99A20664 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727809AbeJaBmz (ORCPT ); Tue, 30 Oct 2018 21:42:55 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:33172 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727602AbeJaBmz (ORCPT ); Tue, 30 Oct 2018 21:42:55 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9UGi5U6072601; Tue, 30 Oct 2018 16:48:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2018-07-02; bh=PB85NKJjKMonzJ73It+n0xbsJw1mcSok7DC4lIgeBjY=; b=Q0uZbiyRg6agko3o1VXUrhemjQNIVpFJTiBQP2R8YNNv0kENOOYdN+vkBQrKUlyIBSlF JU4janxIdkP5dQfPgbIgzqDBSIUZ1Xc1BfYdl00uhs870JJaRxJKG3HLGLt4eiQA8bKL /kHXRJ1KS++0Q/AgzteQIqYajSRupQm4Su1nv32qutsrgPUs9fFrf/H+sLBLO20An+Sc GsZIqTmyZqICdj+GJZW4cyauox2kqONhu1bXjkFWPyN8hr3n4paoZoDHkCuHhM4OGK0N /3QheHYycc5v8abWAsk9sRdym/lpyPQ+GWFX+FaXDNoXG0DzFFnphwtrkIQPhzLRhzeF uA== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2130.oracle.com with ESMTP id 2nducm2anx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Oct 2018 16:48:34 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9UGmXx6026605 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Oct 2018 16:48:33 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w9UGmXEv001185; Tue, 30 Oct 2018 16:48:33 GMT Received: from manjunathpatil.us.oracle.com (/10.211.44.52) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 30 Oct 2018 09:48:33 -0700 From: Manjunath Patil To: boris.ostrovsky@oracle.com, jgross@suse.com, konrad.wilk@oracle.com, roger.pau@citrix.com Cc: axboe@kernel.dk, xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path Date: Tue, 30 Oct 2018 09:49:21 -0700 Message-Id: <1540918161-31283-1-git-send-email-manjunath.b.patil@oracle.com> X-Mailer: git-send-email 1.7.1 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9062 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=996 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810300142 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org info->nr_rings isn't adjusted in case of ENOMEM error from negotiate_mq(). This leads to kernel panic in error path. Typical call stack involving panic - #8 page_fault at ffffffff8175936f [exception RIP: blkif_free_ring+33] RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 ... #9 blkif_free at ffffffffa0149aaa [xen_blkfront] #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] #12 xenbus_otherend_changed at ffffffff81424670 #13 backend_changed at ffffffff81426dc3 #14 xenwatch_thread at ffffffff81422f29 #15 kthread at ffffffff810abe6a #16 ret_from_fork at ffffffff81754078 Cc: stable@vger.kernel.org Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") Signed-off-by: Manjunath Patil --- drivers/block/xen-blkfront.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 429d201..5d84da2 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1919,6 +1919,7 @@ static int negotiate_mq(struct blkfront_info *info) GFP_KERNEL); if (!info->rinfo) { xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); + info->nr_rings = 0; return -ENOMEM; } -- 1.7.1