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=-9.0 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,USER_AGENT_GIT autolearn=unavailable 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 57865C169C4 for ; Mon, 11 Feb 2019 15:59:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24DF4218D8 for ; Mon, 11 Feb 2019 15:59:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549900777; bh=pTMd+lyYtkfH2wDSUnDK8s//d3oxhX1AYWYD9xZRm70=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ApUKt0BfzJYL8FuoykCy3W7C4euuavd/rt20S6nOGSA0BO8T18Mp64eGhBKsQZwjk EFDFFE8XzVx9gSFWuV39+aYoKD6nG/JbehUg0YJmNpNlDXOjOjEBFo4+xGkvwd27o6 fcWvJRd5xTXAfyZdRgeu/oMMPSLsuJMmNDjmViVc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730410AbfBKOcG (ORCPT ); Mon, 11 Feb 2019 09:32:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:39288 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729890AbfBKOcF (ORCPT ); Mon, 11 Feb 2019 09:32:05 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (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 F161620838; Mon, 11 Feb 2019 14:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895524; bh=pTMd+lyYtkfH2wDSUnDK8s//d3oxhX1AYWYD9xZRm70=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=soZEjD84L8QaaRpN38Pm+YDsXjSSWJqj2+nBGbqawh6FR5DbrproDGSan9QPA8CER SqHxJWNQGST1lixXqhJ/S5D9hAOf5yg6RnYm8mb5+BY9ykJ8gCBUK6tEQ/DMn29gRw u4f5zZO3cOsQgegWQ8gfQv9q1UUHxx8YLLvoAF+4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guoqing Jiang , Shaohua Li , Sasha Levin , =?UTF-8?q?Sini=C5=A1a=20Bandin?= Subject: [PATCH 4.20 233/352] md: fix raid10 hang issue caused by barrier Date: Mon, 11 Feb 2019 15:17:40 +0100 Message-Id: <20190211141902.031847579@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141846.543045703@linuxfoundation.org> References: <20190211141846.543045703@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit e820d55cb99dd93ac2dc949cf486bb187e5cd70d ] When both regular IO and resync IO happen at the same time, and if we also need to split regular. Then we can see tasks hang due to barrier. 1. resync thread [ 1463.757205] INFO: task md1_resync:5215 blocked for more than 480 seconds. [ 1463.757207] Not tainted 4.19.5-1-default #1 [ 1463.757209] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1463.757212] md1_resync D 0 5215 2 0x80000000 [ 1463.757216] Call Trace: [ 1463.757223] ? __schedule+0x29a/0x880 [ 1463.757231] ? raise_barrier+0x8d/0x140 [raid10] [ 1463.757236] schedule+0x78/0x110 [ 1463.757243] raise_barrier+0x8d/0x140 [raid10] [ 1463.757248] ? wait_woken+0x80/0x80 [ 1463.757257] raid10_sync_request+0x1f6/0x1e30 [raid10] [ 1463.757265] ? _raw_spin_unlock_irq+0x22/0x40 [ 1463.757284] ? is_mddev_idle+0x125/0x137 [md_mod] [ 1463.757302] md_do_sync.cold.78+0x404/0x969 [md_mod] [ 1463.757311] ? wait_woken+0x80/0x80 [ 1463.757336] ? md_rdev_init+0xb0/0xb0 [md_mod] [ 1463.757351] md_thread+0xe9/0x140 [md_mod] [ 1463.757358] ? _raw_spin_unlock_irqrestore+0x2e/0x60 [ 1463.757364] ? __kthread_parkme+0x4c/0x70 [ 1463.757369] kthread+0x112/0x130 [ 1463.757374] ? kthread_create_worker_on_cpu+0x40/0x40 [ 1463.757380] ret_from_fork+0x3a/0x50 2. regular IO [ 1463.760679] INFO: task kworker/0:8:5367 blocked for more than 480 seconds. [ 1463.760683] Not tainted 4.19.5-1-default #1 [ 1463.760684] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1463.760687] kworker/0:8 D 0 5367 2 0x80000000 [ 1463.760718] Workqueue: md submit_flushes [md_mod] [ 1463.760721] Call Trace: [ 1463.760731] ? __schedule+0x29a/0x880 [ 1463.760741] ? wait_barrier+0xdd/0x170 [raid10] [ 1463.760746] schedule+0x78/0x110 [ 1463.760753] wait_barrier+0xdd/0x170 [raid10] [ 1463.760761] ? wait_woken+0x80/0x80 [ 1463.760768] raid10_write_request+0xf2/0x900 [raid10] [ 1463.760774] ? wait_woken+0x80/0x80 [ 1463.760778] ? mempool_alloc+0x55/0x160 [ 1463.760795] ? md_write_start+0xa9/0x270 [md_mod] [ 1463.760801] ? try_to_wake_up+0x44/0x470 [ 1463.760810] raid10_make_request+0xc1/0x120 [raid10] [ 1463.760816] ? wait_woken+0x80/0x80 [ 1463.760831] md_handle_request+0x121/0x190 [md_mod] [ 1463.760851] md_make_request+0x78/0x190 [md_mod] [ 1463.760860] generic_make_request+0x1c6/0x470 [ 1463.760870] raid10_write_request+0x77a/0x900 [raid10] [ 1463.760875] ? wait_woken+0x80/0x80 [ 1463.760879] ? mempool_alloc+0x55/0x160 [ 1463.760895] ? md_write_start+0xa9/0x270 [md_mod] [ 1463.760904] raid10_make_request+0xc1/0x120 [raid10] [ 1463.760910] ? wait_woken+0x80/0x80 [ 1463.760926] md_handle_request+0x121/0x190 [md_mod] [ 1463.760931] ? _raw_spin_unlock_irq+0x22/0x40 [ 1463.760936] ? finish_task_switch+0x74/0x260 [ 1463.760954] submit_flushes+0x21/0x40 [md_mod] So resync io is waiting for regular write io to complete to decrease nr_pending (conf->barrier++ is called before waiting). The regular write io splits another bio after call wait_barrier which call nr_pending++, then the splitted bio would continue with raid10_write_request -> wait_barrier, so the splitted bio has to wait for barrier to be zero, then deadlock happens as follows. resync io regular io raise_barrier wait_barrier generic_make_request wait_barrier To resolve the issue, we need to call allow_barrier to decrease nr_pending before generic_make_request since regular IO is not issued to underlying devices, and wait_barrier is called again to ensure no internal IO happening. Fixes: fc9977dd069e ("md/raid10: simplify the splitting of requests.") Reported-and-tested-by: SiniĊĦa Bandin Signed-off-by: Guoqing Jiang Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin --- drivers/md/raid10.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index b98e746e7fc4..12cf8a04e839 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1209,7 +1209,9 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, struct bio *split = bio_split(bio, max_sectors, gfp, &conf->bio_split); bio_chain(split, bio); + allow_barrier(conf); generic_make_request(bio); + wait_barrier(conf); bio = split; r10_bio->master_bio = bio; r10_bio->sectors = max_sectors; @@ -1514,7 +1516,9 @@ retry_write: struct bio *split = bio_split(bio, r10_bio->sectors, GFP_NOIO, &conf->bio_split); bio_chain(split, bio); + allow_barrier(conf); generic_make_request(bio); + wait_barrier(conf); bio = split; r10_bio->master_bio = bio; } -- 2.19.1