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 CC9D3C43331 for ; Fri, 27 Mar 2020 10:02:16 +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 9FF33206F8 for ; Fri, 27 Mar 2020 10:02:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FF33206F8 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]:39444 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHlod-00017o-Ok for qemu-devel@archiver.kernel.org; Fri, 27 Mar 2020 06:02:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48441) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jHlne-0000fU-CU for qemu-devel@nongnu.org; Fri, 27 Mar 2020 06:01:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jHlnZ-00073S-8r for qemu-devel@nongnu.org; Fri, 27 Mar 2020 06:01:14 -0400 Received: from proxmox-new.maurer-it.com ([212.186.127.180]:13097) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jHlnS-0006fZ-Dy; Fri, 27 Mar 2020 06:01:02 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 3001C428FF; Fri, 27 Mar 2020 11:00:50 +0100 (CET) Date: Fri, 27 Mar 2020 11:00:48 +0100 (CET) From: Dietmar Maurer To: Stefan Reiter , qemu-devel@nongnu.org, qemu-block@nongnu.org Message-ID: <626397594.17.1585303248535@webmail.proxmox.com> In-Reply-To: <20200326155628.859862-1-s.reiter@proxmox.com> References: <20200326155628.859862-1-s.reiter@proxmox.com> Subject: Re: [PATCH v2 0/3] Fix some AIO context locking in jobs 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-Rev22 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: kwolf@redhat.com, vsementsov@virtuozzo.com, slp@redhat.com, mreitz@redhat.com, stefanha@redhat.com, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > I *think* the second patch also fixes the hangs on backup abort that I and > Dietmar noticed in v1, but I'm not sure, they we're somewhat intermittent > before too. After more test, I am 100% sure the bug (or another one) is still there. Here is how to trigger: 1. use latest qemu sources from githup 2. apply those 3 patches from Stefan 2. create a VM with virtio-scsis-single drive using io-thread 3. inside VM install Debian buster 4. inside VM, run "stress -d 5" Then run a series of backups, aborting them after a few seconds: # start loop qmp: { "execute": "drive-backup", "arguments": { "device": "drive-scsi0", "sync": "full", "target": "backup-scsi0.raw" } } sleep 3 second qmp: { "execute": "'block-job-cancel", "arguments": { "device": "drive-scsi0" } } # end loop After several iterations (mostly < 50) the VM freezes (this time somewhere inside drive_backup_prepare): (gdb) bt #0 0x00007f61ea09e916 in __GI_ppoll (fds=0x7f6158130c40, nfds=2, timeout=, timeout@entry=0x0, sigmask=sigmask@entry=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39 #1 0x000055f708401c79 in ppoll (__ss=0x0, __timeout=0x0, __nfds=, __fds=) at /usr/include/x86_64-linux-gnu/bits/poll2.h:77 #2 0x000055f708401c79 in qemu_poll_ns (fds=, nfds=, timeout=timeout@entry=-1) at util/qemu-timer.c:335 #3 0x000055f708404461 in fdmon_poll_wait (ctx=0x7f61dcd05e80, ready_list=0x7ffc4e7fbde8, timeout=-1) at util/fdmon-poll.c:79 #4 0x000055f708403a47 in aio_poll (ctx=0x7f61dcd05e80, blocking=blocking@entry=true) at util/aio-posix.c:589 #5 0x000055f708364c03 in bdrv_do_drained_begin (poll=, ignore_bds_parents=false, parent=0x0, recursive=false, bs=0x7f61dcd4c500) at block/io.c:429 #6 0x000055f708364c03 in bdrv_do_drained_begin (bs=0x7f61dcd4c500, recursive=, parent=0x0, ignore_bds_parents=, poll=) at block/io.c:395 #7 0x000055f7081016f9 in drive_backup_prepare (common=0x7f61d9a0c280, errp=0x7ffc4e7fbf28) at blockdev.c:1755 #8 0x000055f708103e6a in qmp_transaction (dev_list=dev_list@entry=0x7ffc4e7fbfa0, has_props=has_props@entry=false, props=0x7f61d9a304e8, props@entry=0x0, errp=errp@entry=0x7ffc4e7fbfd8) at blockdev.c:2401 #9 0x000055f708105322 in blockdev_do_action (errp=0x7ffc4e7fbfd8, action=0x7ffc4e7fbf90) at blockdev.c:1054 #10 0x000055f708105322 in qmp_drive_backup (backup=backup@entry=0x7ffc4e7fbfe0, errp=errp@entry=0x7ffc4e7fbfd8) at blockdev.c:3129 #11 0x000055f7082c0101 in qmp_marshal_drive_backup (args=, ret=, errp=0x7ffc4e7fc0b8) at qapi/qapi-commands-block-core.c:555 #12 0x000055f7083b7338 in qmp_dispatch (cmds=0x55f708904000 , request=, allow_oob=) at qapi/qmp-dispatch.c:155 #13 0x000055f7082a1bd1 in monitor_qmp_dispatch (mon=0x7f61dcd15d80, req=) at monitor/qmp.c:145 #14 0x000055f7082a23ba in monitor_qmp_bh_dispatcher (data=) at monitor/qmp.c:234 #15 0x000055f708400205 in aio_bh_call (bh=0x7f61dd28f960) at util/async.c:164 #16 0x000055f708400205 in aio_bh_poll (ctx=ctx@entry=0x7f61dd33ef80) at util/async.c:164 #17 0x000055f70840388e in aio_dispatch (ctx=0x7f61dd33ef80) at util/aio-posix.c:380 #18 0x000055f7084000ee in aio_ctx_dispatch (source=, callback=, user_data=) at util/async.c:298 #19 0x00007f61ec069f2e in g_main_context_dispatch () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 #20 0x000055f708402af8 in glib_pollfds_poll () at util/main-loop.c:219 #21 0x000055f708402af8 in os_host_main_loop_wait (timeout=) at util/main-loop.c:242 #22 0x000055f708402af8 in main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:518 #23 0x000055f70809e589 in qemu_main_loop () at /home/dietmar/pve5-devel/mirror_qemu/softmmu/vl.c:1665 #24 0x000055f707fa2c3e in main (argc=, argv=, envp=) at /home/dietmar/pve5-devel/mirror_qemu/softmmu/main.c:49