From nobody Mon Apr 29 15:51:53 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1517326980072673.1812002893894; Tue, 30 Jan 2018 07:43:00 -0800 (PST) Received: from localhost ([::1]:44210 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1egY3n-0005QY-AY for importer@patchew.org; Tue, 30 Jan 2018 10:42:59 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58759) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1egY09-0002ft-S3 for qemu-devel@nongnu.org; Tue, 30 Jan 2018 10:39:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1egY08-0007ug-Uf for qemu-devel@nongnu.org; Tue, 30 Jan 2018 10:39:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37200) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1egY03-0007sd-MR; Tue, 30 Jan 2018 10:39:07 -0500 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 mx1.redhat.com (Postfix) with ESMTPS id EA05A5F7B9; Tue, 30 Jan 2018 15:39:06 +0000 (UTC) Received: from localhost (ovpn-116-199.ams2.redhat.com [10.36.116.199]) by smtp.corp.redhat.com (Postfix) with ESMTP id 35CC05C261; Tue, 30 Jan 2018 15:38:52 +0000 (UTC) From: Stefan Hajnoczi To: Date: Tue, 30 Jan 2018 15:38:35 +0000 Message-Id: <20180130153835.7372-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 30 Jan 2018 15:39:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] vl: pause vcpus before stopping iothreads X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , Stefan Hajnoczi , qemu-block@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Commit dce8921b2baaf95974af8176406881872067adfa ("iothread: Stop threads before main() quits") introduced iothread_stop_all() to avoid the following virtio-scsi assertion failure: assert(blk_get_aio_context(d->conf.blk) =3D=3D s->ctx); Back then the assertion failed because when bdrv_close_all() made d->conf.blk NULL, blk_get_aio_context() returned the global AioContext instead of s->ctx. The same assertion can still fail today when vcpus submit new I/O requests after iothread_stop_all() has moved the BDS to the global AioContext. This patch hardens the iothread_stop_all() approach by pausing vcpus before calling iothread_stop_all(). Note that the assertion failure is a race condition. It is not possible to reproduce it reliably. Signed-off-by: Stefan Hajnoczi Reviewed-by: Kevin Wolf --- vl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/vl.c b/vl.c index e517a8d995..011f22ae20 100644 --- a/vl.c +++ b/vl.c @@ -4765,10 +4765,10 @@ int main(int argc, char **argv, char **envp) os_setup_post(); =20 main_loop(); + replay_disable_events(); + pause_all_vcpus(); iothread_stop_all(); - - pause_all_vcpus(); bdrv_close_all(); res_free(); =20 --=20 2.14.3