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=-6.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 755E1C43610 for ; Sun, 11 Nov 2018 22:31:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22F0C223DD for ; Sun, 11 Nov 2018 22:31:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="BRDlbkVQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 22F0C223DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S2389703AbeKLIVc (ORCPT ); Mon, 12 Nov 2018 03:21:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:47942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732161AbeKLIV3 (ORCPT ); Mon, 12 Nov 2018 03:21:29 -0500 Received: from localhost (unknown [206.108.79.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7EE392175B; Sun, 11 Nov 2018 22:31:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541975491; bh=3Umkxu1+swxYlZY8OViUymYaNQaBhAwl+NhF56wDJRk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BRDlbkVQ5i0fLD4hMoS2n2hYUCLQrvhjLpfyCAsFpfqbUz25EPacW19dw+WCcx6Lm cvECWRP7w8L5Ssk8gYo3dAHh0YsX1qtso7LhVAm2Ut/XnDd/NQNaybBGisdI/cZpns 4jQNe5YNKEBJoyjOI9mV8pt6nFdeaeDG0r/o/tQc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Manjunath Patil , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Juergen Gross Subject: [PATCH 4.18 292/350] xen-blkfront: fix kernel panic with negotiate_mq error path Date: Sun, 11 Nov 2018 14:22:36 -0800 Message-Id: <20181111221720.291380826@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181111221707.043394111@linuxfoundation.org> References: <20181111221707.043394111@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Manjunath Patil commit 6cc4a0863c9709c512280c64e698d68443ac8053 upstream. 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 Acked-by: Roger Pau Monné Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- drivers/block/xen-blkfront.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1911,6 +1911,7 @@ static int negotiate_mq(struct blkfront_ GFP_KERNEL); if (!info->rinfo) { xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); + info->nr_rings = 0; return -ENOMEM; }