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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 C9CEDC43331 for ; Thu, 2 Apr 2020 09:11:12 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5CBC920719 for ; Thu, 2 Apr 2020 09:11:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5CBC920719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=proxmox.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35754 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jJvsS-0008Np-FR for qemu-devel@archiver.kernel.org; Thu, 02 Apr 2020 05:11:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50201) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jJvrn-0007l0-IZ for qemu-devel@nongnu.org; Thu, 02 Apr 2020 05:10:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jJvrm-00016u-Kt for qemu-devel@nongnu.org; Thu, 02 Apr 2020 05:10:27 -0400 Received: from proxmox-new.maurer-it.com ([212.186.127.180]:51619) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jJvrk-000144-GY; Thu, 02 Apr 2020 05:10:24 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id EB47945960; Thu, 2 Apr 2020 11:10:20 +0200 (CEST) Date: Thu, 2 Apr 2020 11:10:19 +0200 (CEST) From: Dietmar Maurer To: Kevin Wolf Message-ID: <903538836.29.1585818619688@webmail.proxmox.com> In-Reply-To: <20200401184431.GD27663@linux.fritz.box> References: <20200331125804.GE7030@linux.fritz.box> <303038276.59.1585665152860@webmail.proxmox.com> <787d7517-bf56-72c7-d197-2313a864e05f@virtuozzo.com> <713436887.61.1585668262838@webmail.proxmox.com> <20200331153719.GI7030@linux.fritz.box> <518198448.62.1585671498399@webmail.proxmox.com> <20200401103748.GA4680@linux.fritz.box> <997901084.0.1585755465486@webmail.proxmox.com> <20200401181256.GB27663@linux.fritz.box> <1403939459.52.1585765681569@webmail.proxmox.com> <20200401184431.GD27663@linux.fritz.box> Subject: Re: bdrv_drained_begin deadlock with io-threads MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Priority: 3 Importance: Normal X-Mailer: Open-Xchange Mailer v7.10.2-Rev23 X-Originating-Client: open-xchange-appsuite X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 212.186.127.180 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Dietmar Maurer Cc: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Sergio Lopez , "qemu-devel@nongnu.org" , Max Reitz , Stefan Hajnoczi , "jsnow@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > It seems to fix it, yes. Now I don't get any hangs any more. I just tested using your configuration, and a recent centos8 image running dd loop inside it: # while dd if=/dev/urandom of=testfile.raw bs=1M count=100; do sync; done With that, I am unable to trigger the bug. Would you mind running the test using a Debian Buster image running "stress-ng -d 5" inside? I (and to other people here) can trigger the bug quite reliable with that. On Debian, you can easily install stress-ng using apt: # apt update # apt install stress-ng Seems stress-ng uses a different write pattern which can trigger the bug more reliable.