From patchwork Fri Nov 29 11:51:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Vivier X-Patchwork-Id: 11267051 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8B0B7921 for ; Fri, 29 Nov 2019 12:13:40 +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 579392086A for ; Fri, 29 Nov 2019 12:13:40 +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="Mz9AdbdT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 579392086A 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:58092 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaf9X-0003sF-Gv for patchwork-qemu-devel@patchwork.kernel.org; Fri, 29 Nov 2019 07:13:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35480) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaeoK-0003mH-88 for qemu-devel@nongnu.org; Fri, 29 Nov 2019 06:51:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iaeoE-0006Gn-3j for qemu-devel@nongnu.org; Fri, 29 Nov 2019 06:51:39 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:23778 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iaeoD-0006D8-Op for qemu-devel@nongnu.org; Fri, 29 Nov 2019 06:51:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575028296; 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; bh=pKLtw685LNIJ0P4Bwry6gDlmSQl/6EnXEUPaX71gWCQ=; b=Mz9AdbdT1N6sQ5kz8noUsRynj/Gg1pzasSGJCamZkp71GA9P+L0i7TIQJXE7TeV26yvV29 QbDuZEyotFbQdVk0K4Bb7WtWHE8ZXfAgw+Wod5ZWODGuFAXLJRrb3PwpvGTl5R9gQzDxPO ady8XaKH2XV5nIFYv0h4MQWNvawm65Y= 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-107-7zr2YFtvM0iZuc5qgL4iyA-1; Fri, 29 Nov 2019 06:51:35 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CA689800D4C for ; Fri, 29 Nov 2019 11:51:34 +0000 (UTC) Received: from thinkpad.redhat.com (ovpn-116-235.ams2.redhat.com [10.36.116.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id A3A6910246E6; Fri, 29 Nov 2019 11:51:33 +0000 (UTC) From: Laurent Vivier To: qemu-devel@nongnu.org Subject: [PATCH] runstate: ignore finishmigrate -> prelaunch transition Date: Fri, 29 Nov 2019 12:51:32 +0100 Message-Id: <20191129115132.285988-1-lvivier@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: 7zr2YFtvM0iZuc5qgL4iyA-1 X-Mimecast-Spam-Score: 0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: Laurent Vivier , Paolo Bonzini , "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Commit 1bd71dce4bf2 tries to prevent a finishmigrate -> prelaunch transition by exiting at the beginning of the main_loop_should_exit() function if the state is already finishmigrate. As the finishmigrate state is set in the migration thread it can happen concurrently to the function. The migration thread and the function are normally protected by the iothread mutex and thus the state should no evolve between the start of the function and its end. Unfortunately during the function life the lock is released by pause_all_vcpus() just before the point we need to be sure we are not in finishmigrate state and if the migration thread is waiting for the lock it will take the opportunity to change the state to finishmigrate. The only way to be sure we are not in the finishmigrate state when we need is to check the state after the pause_all_vcpus() function. Fixes: 1bd71dce4bf2 ("runstate: ignore exit request in finish migrate state") Signed-off-by: Laurent Vivier Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela --- vl.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/vl.c b/vl.c index 6a65a64bfd64..bf0a6345d239 100644 --- a/vl.c +++ b/vl.c @@ -1745,9 +1745,6 @@ static bool main_loop_should_exit(void) RunState r; ShutdownCause request; - if (runstate_check(RUN_STATE_FINISH_MIGRATE)) { - return false; - } if (preconfig_exit_requested) { if (runstate_check(RUN_STATE_PRECONFIG)) { runstate_set(RUN_STATE_PRELAUNCH); @@ -1776,8 +1773,13 @@ static bool main_loop_should_exit(void) pause_all_vcpus(); qemu_system_reset(request); resume_all_vcpus(); + /* + * runstate can change in pause_all_vcpus() + * as iothread mutex is unlocked + */ if (!runstate_check(RUN_STATE_RUNNING) && - !runstate_check(RUN_STATE_INMIGRATE)) { + !runstate_check(RUN_STATE_INMIGRATE) && + !runstate_check(RUN_STATE_FINISH_MIGRATE)) { runstate_set(RUN_STATE_PRELAUNCH); } }