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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 18D0AC43441 for ; Thu, 8 Nov 2018 22:42:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFD2E20844 for ; Thu, 8 Nov 2018 22:42:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="HS2fwmY1" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFD2E20844 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 S1728931AbeKIHdg (ORCPT ); Fri, 9 Nov 2018 02:33:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:49234 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727979AbeKIHdf (ORCPT ); Fri, 9 Nov 2018 02:33:35 -0500 Received: from localhost (unknown [208.72.13.198]) (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 6614220989; Thu, 8 Nov 2018 21:56:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541714168; bh=/eN8I6diW1pbQM6bLYyyyNPM2u62KXmSQuctOGPD1TU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HS2fwmY1j5BZ3eBk2tGQjhe2ZBs/luHWHAiCUyimhxGJl8tUyMaSvdhIqfaAny8Dk +0dI/AIPO8c6EVySW+e2FWjMnlbRlNp1lbuElqm8jQj9k4e93/DehJeeIVoraGg9QT pYyutr32csWtHE8ogzFdaWap+nDCGD+up7rMsnjw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Junichi Nomura , Mikulas Patocka , Mike Snitzer , Sasha Levin Subject: [PATCH 3.18 089/144] dm: fix AB-BA deadlock in __dm_destroy() Date: Thu, 8 Nov 2018 13:51:00 -0800 Message-Id: <20181108215101.858874763@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181108215054.826084593@linuxfoundation.org> References: <20181108215054.826084593@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 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 2a708cff93f1845b9239bc7d6310aef54e716c6a ] __dm_destroy() takes io_barrier SRCU lock (dm_get_live_table) and suspend_lock in reverse order. Doing so can cause AB-BA deadlock: __dm_destroy dm_swap_table --------------------------------------------------- mutex_lock(suspend_lock) dm_get_live_table() srcu_read_lock(io_barrier) dm_sync_table() synchronize_srcu(io_barrier) .. waiting for dm_put_live_table() mutex_lock(suspend_lock) .. waiting for suspend_lock Fix this by taking the locks in proper order. Signed-off-by: Jun'ichi Nomura Fixes: ab7c7bb6f4ab ("dm: hold suspend_lock while suspending device during device deletion") Acked-by: Mikulas Patocka Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin --- drivers/md/dm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1d08dc6fa0b5..00c86ff3c721 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2599,14 +2599,14 @@ static void __dm_destroy(struct mapped_device *md, bool wait) * do not race with internal suspend. */ mutex_lock(&md->suspend_lock); + map = dm_get_live_table(md, &srcu_idx); if (!dm_suspended_md(md)) { dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); } - mutex_unlock(&md->suspend_lock); - /* dm_put_live_table must be before msleep, otherwise deadlock is possible */ dm_put_live_table(md, srcu_idx); + mutex_unlock(&md->suspend_lock); /* * Rare, but there may be I/O requests still going to complete, -- 2.17.1