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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B1327C47082 for ; Tue, 8 Jun 2021 14:08:26 +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 53A5960FE9 for ; Tue, 8 Jun 2021 14:08:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53A5960FE9 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]:55480 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lqcP3-00022v-6R for qemu-devel@archiver.kernel.org; Tue, 08 Jun 2021 10:08:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53216) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqcOS-0001NY-De for qemu-devel@nongnu.org; Tue, 08 Jun 2021 10:07:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60957) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqcON-0000fk-Oi for qemu-devel@nongnu.org; Tue, 08 Jun 2021 10:07:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623161262; 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: in-reply-to:in-reply-to:references:references; bh=L+XshwnpLQ4ETr1+CpvOStuZ0FTFhtpbHHBiYzQWI9Y=; b=crF0WFAJJNI/OAiBsnoV1CsjFADugZfgIDccpfA3gfed5lkqjN9nNgiyuFJ4y+iZZPKDSl 8bu1btVDKL+XZ3o7QyadCFMdu6E0xCCmDx/4cayr0CHcuIJOqUr3kv6B7xdCx+0RhSJ11b PaQ+thB3qjmywFcVBfTbd2rqA1MWfy8= 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-595-KYW6fqS2NnKdqpDZ5C8iYA-1; Tue, 08 Jun 2021 10:07:41 -0400 X-MC-Unique: KYW6fqS2NnKdqpDZ5C8iYA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 604C3101371B; Tue, 8 Jun 2021 14:07:40 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-222.ams2.redhat.com [10.36.112.222]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2AE2B5C1BB; Tue, 8 Jun 2021 14:07:32 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id B53CF113865F; Tue, 8 Jun 2021 16:07:30 +0200 (CEST) From: Markus Armbruster To: "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" Subject: Re: A bug of Monitor Chardev ? References: Date: Tue, 08 Jun 2021 16:07:30 +0200 In-Reply-To: (Longpeng's message of "Mon, 17 May 2021 14:56:39 +0800") Message-ID: <87o8cgxxel.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=216.205.24.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.197, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: chenjiashang@huawei.com, =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , qemu-devel@nongnu.org, Peter Xu , "Gonglei \(Arei\)" , pbonzini@redhat.com, marcandre.lureau@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" writes: > We find a race during QEMU starting, which would case the QEMU process coredump. > >
| > | > [1] create MON chardev | > qemu_create_early_backends | > chardev_init_func | > | > [2] create MON iothread | > qemu_create_late_backends | > mon_init_func | > aio_bh_schedule-----------------------> monitor_qmp_setup_handlers_bh > [3] enter main loog | tcp_chr_update_read_handler > (* A client come in, e.g. Libvirt *) | update_ioc_handlers > tcp_chr_new_client | > update_ioc_handlers | > | > [4] create new hup_source | > s->hup_source = *PTR1* | > g_source_attach(s->hup_source)| > | [5] remove_hup_source(*PTR1*) > | (create new hup_source) > | s->hup_source = *PTR2* > [6] g_source_attach_unlocked | > *PTR1* is freed by [5] | > > Do you have any suggestion to fix this bug ? Thanks! Do we? We talked, but I'm not sure we reached a conclusion.