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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 ECD3FC433E0 for ; Mon, 18 May 2020 02:53:27 +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 A9FB220787 for ; Mon, 18 May 2020 02:53:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="f3i/Kq9b" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9FB220787 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jaVuA-0000SQ-UQ for qemu-devel@archiver.kernel.org; Sun, 17 May 2020 22:53:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33010) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jaVtF-0008IB-QI for qemu-devel@nongnu.org; Sun, 17 May 2020 22:52:29 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:35314 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jaVtE-0004kX-Ly for qemu-devel@nongnu.org; Sun, 17 May 2020 22:52:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589770347; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FtRk+bnwwNwWWxyCnlhR5aQjzZOFMJcUYzcyDGLbM5k=; b=f3i/Kq9bmKySCLHtr+2jz/P3Ar0eGuYFyIgt0hcrpw6RCl3xtlf/lSR9QbM15SYeFLP11V BV8+yUtqwGGhyZSWnc6EzhWQKLlkaKrhTxJACaPMgfWY/YdusPW+GtGTCOh2VVnhZdiNGG cZSQ8EClz+1zbSxI9VlgUJY5AzxXzb0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-429-7p8Xl5BcOhe11V8WfyUGhg-1; Sun, 17 May 2020 22:52:26 -0400 X-MC-Unique: 7p8Xl5BcOhe11V8WfyUGhg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ED644835B40; Mon, 18 May 2020 02:52:24 +0000 (UTC) Received: from [10.72.13.232] (ovpn-13-232.pek2.redhat.com [10.72.13.232]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3CEF15F7EA; Mon, 18 May 2020 02:52:09 +0000 (UTC) Subject: Re: [PATCH v2 5/5] vhost: add device started check in migration set log To: Li Feng , Dima Stepanov References: <20200511092541.GA27558@dimastep-nix> <20200512093521.GA5363@dimastep-nix> <20200512235934-mutt-send-email-mst@kernel.org> <20200513094703.GA15906@dimastep-nix> <722839b2-9412-b768-3ce6-d1b697d6d5dd@redhat.com> <20200515165449.GA1627@dimastep-nix> From: Jason Wang Message-ID: <6bf8a077-01fb-dfd1-164e-440d313503d3@redhat.com> Date: Mon, 18 May 2020 10:52:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/17 22:52:27 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: , Cc: Fam Zheng , Kevin Wolf , Stefan Hajnoczi , "open list:Block layer core" , "Michael S. Tsirkin" , "open list:All patches CC here" , "Dr. David Alan Gilbert" , Gonglei , yc-core@yandex-team.ru, Paolo Bonzini , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Raphael Norwitz , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/5/16 上午11:20, Li Feng wrote: > Hi, Dima. > This abort is what I have mentioned in my previous email. > I have triggered this crash without any fix a week ago. > And I have written a test patch to let vhost_log_global_start return > int and propagate the error to up layer. > However, my change is a little large, because the origin callback > return void, and don't do some rollback. > After test, the migration could migrate to dst successfully, and fio > is still running perfectly, but the src vm is still stuck here, no > crash. > > Is it right to return this error to the up layer? That could be a solution or we may ask David for more suggestion. Another thing that might be useful is to block re connection during migration. Thanks > > Thanks, > Feng Li > > Dima Stepanov 于2020年5月16日周六 上午12:55写道： >> On Thu, May 14, 2020 at 03:34:24PM +0800, Jason Wang wrote: >>> On 2020/5/13 下午5:47, Dima Stepanov wrote: >>>>>> case CHR_EVENT_CLOSED: >>>>>> /* a close event may happen during a read/write, but vhost >>>>>> * code assumes the vhost_dev remains setup, so delay the >>>>>> * stop & clear to idle. >>>>>> * FIXME: better handle failure in vhost code, remove bh >>>>>> */ >>>>>> if (s->watch) { >>>>>> AioContext *ctx = qemu_get_current_aio_context(); >>>>>> >>>>>> g_source_remove(s->watch); >>>>>> s->watch = 0; >>>>>> qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, NULL, NULL, >>>>>> NULL, NULL, false); >>>>>> >>>>>> aio_bh_schedule_oneshot(ctx, chr_closed_bh, opaque); >>>>>> } >>>>>> break; >>>>>> >>>>>> I think it's time we dropped the FIXME and moved the handling to common >>>>>> code. Jason? Marc-André? >>>>> I agree. Just to confirm, do you prefer bh or doing changes like what is >>>>> done in this series? It looks to me bh can have more easier codes. >>>> Could it be a good idea just to make disconnect in the char device but >>>> postphone clean up in the vhost-user-blk (or any other vhost-user >>>> device) itself? So we are moving the postphone logic and decision from >>>> the char device to vhost-user device. One of the idea i have is as >>>> follows: >>>> - Put ourself in the INITIALIZATION state >>>> - Start these vhost-user "handshake" commands >>>> - If we got a disconnect error, perform disconnect, but don't clean up >>>> device (it will be clean up on the roll back). I can be done by >>>> checking the state in vhost_user_..._disconnect routine or smth like it >>> >>> Any issue you saw just using the aio bh as Michael posted above. >>> >>> Then we don't need to deal with the silent vhost_dev_stop() and we will have >>> codes that is much more easier to understand. >> I've implemented this solution inside >> hw/block/vhost-user-blk.c:vhost_user_blk_event() in the similar way by >> using the s->connected field. Looks good and more correct fix ). I have >> two questions here before i'll rework the fixes: >> 1. Is it okay to make the similar fix inside vhost_user_blk_event() or >> we are looking for more generic vhost-user solution? What do you think? >> 2. For migration we require an additional information that for the >> vhost-user device it isn't an error, because i'm trigerring the >> following assert error: >> Core was generated by `x86_64-softmmu/qemu-system-x86_64 -nodefaults -no-user-config -M q35,sata=false'. >> Program terminated with signal SIGABRT, Aborted. >> #0 0x00007fb56e729428 in raise () from /lib/x86_64-linux-gnu/libc.so.6 >> [Current thread is 1 (Thread 0x7fb486ef5700 (LWP 527734))] >> >> (gdb) bt >> #0 0x00007fb56e729428 in raise () from /lib/x86_64-linux-gnu/libc.so.6 >> #1 0x00007fb56e72b02a in abort () from /lib/x86_64-linux-gnu/libc.so.6 >> #2 0x00005648ea376ee6 in vhost_log_global_start >> (listener=0x5648ece4eb08) at ./hw/virtio/vhost.c:857 >> #3 0x00005648ea2dde7e in memory_global_dirty_log_start () >> at ./memory.c:2611 >> #4 0x00005648ea2e68e7 in ram_init_bitmaps (rs=0x7fb4740008c0) >> at ./migration/ram.c:2305 >> #5 0x00005648ea2e698b in ram_init_all (rsp=0x5648eb1f0f20 ) >> at ./migration/ram.c:2323 >> #6 0x00005648ea2e6cc5 in ram_save_setup (f=0x5648ec609e00, >> opaque=0x5648eb1f0f20 ) >> at ./migration/ram.c:2436 >> #7 0x00005648ea67b7d3 in qemu_savevm_state_setup (f=0x5648ec609e00) at >> migration/savevm.c:1176 >> #8 0x00005648ea674511 in migration_thread (opaque=0x5648ec031ff0) at >> migration/migration.c:3416 >> #9 0x00005648ea85d65d in qemu_thread_start (args=0x5648ec6057f0) at >> util/qemu-thread-posix.c:519 >> #10 0x00007fb56eac56ba in start_thread () from >> /lib/x86_64-linux-gnu/libpthread.so.0 >> #11 0x00007fb56e7fb41d in clone () from /lib/x86_64-linux-gnu/libc.so.6 >> (gdb) frame 2 >> #2 0x00005648ea376ee6 in vhost_log_global_start >> (listener=0x5648ece4eb08) at ./hw/virtio/vhost.c:857 >> 857 abort(); >> (gdb) list >> 852 { >> 853 int r; >> 854 >> 855 r = vhost_migration_log(listener, true); >> 856 if (r < 0) { >> 857 abort(); >> 858 } >> 859 } >> 860 >> 861 static void vhost_log_global_stop(MemoryListener *listener) >> Since bh postphone the clean up, we can't use the ->started field. >> Do we have any mechanism to get the device type/state in the common >> vhost_migration_log() routine? So for example for the vhost-user/disconnect >> device we will be able to return 0. Or should we implement it and introduce >> it in this patch set? >> >> Thanks, Dima. >> >>> Thank >>> >>> >>>> - vhost-user command returns error back to the _start() routine >>>> - Rollback in one place in the start() routine, by calling this >>>> postphoned clean up for the disconnect >>>>