From nobody Sun Feb 8 09:42:33 2026 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; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1536337791751183.76753847784164; Fri, 7 Sep 2018 09:29:51 -0700 (PDT) Received: from localhost ([::1]:39520 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fyJdd-00025D-Qx for importer@patchew.org; Fri, 07 Sep 2018 12:29:41 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53539) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fyJQn-0006Pm-77 for qemu-devel@nongnu.org; Fri, 07 Sep 2018 12:16:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fyJQg-0004Un-HP for qemu-devel@nongnu.org; Fri, 07 Sep 2018 12:16:19 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56198 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fyJQV-000488-0A; Fri, 07 Sep 2018 12:16:07 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 05C0F40241DC; Fri, 7 Sep 2018 16:16:06 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-116-56.ams2.redhat.com [10.36.116.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id A34072157F49; Fri, 7 Sep 2018 16:16:04 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Fri, 7 Sep 2018 18:15:20 +0200 Message-Id: <20180907161520.26349-15-kwolf@redhat.com> In-Reply-To: <20180907161520.26349-1-kwolf@redhat.com> References: <20180907161520.26349-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 07 Sep 2018 16:16:06 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Fri, 07 Sep 2018 16:16:06 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'kwolf@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 14/14] test-bdrv-drain: Test nested poll in bdrv_drain_poll_top_level() 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: kwolf@redhat.com, famz@redhat.com, slp@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RDMRC_1 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This is a regression test for a deadlock that could occur in callbacks called from the aio_poll() in bdrv_drain_poll_top_level(). The AioContext lock wasn't released and therefore would be taken a second time in the callback. This would cause a possible AIO_WAIT_WHILE() in the callback to hang. Signed-off-by: Kevin Wolf --- tests/test-bdrv-drain.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c index 9641a20dd8..07ce5bfddc 100644 --- a/tests/test-bdrv-drain.c +++ b/tests/test-bdrv-drain.c @@ -636,6 +636,17 @@ static void test_iothread_aio_cb(void *opaque, int ret) qemu_event_set(&done_event); } =20 +static void test_iothread_main_thread_bh(void *opaque) +{ + struct test_iothread_data *data =3D opaque; + + /* Test that the AioContext is not yet locked in a random BH that is + * executed during drain, otherwise this would deadlock. */ + aio_context_acquire(bdrv_get_aio_context(data->bs)); + bdrv_flush(data->bs); + aio_context_release(bdrv_get_aio_context(data->bs)); +} + /* * Starts an AIO request on a BDS that runs in the AioContext of iothread = 1. * The request involves a BH on iothread 2 before it can complete. @@ -705,6 +716,8 @@ static void test_iothread_common(enum drain_type drain_= type, int drain_thread) aio_context_acquire(ctx_a); } =20 + aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data= ); + /* The request is running on the IOThread a. Draining its block de= vice * will make sure that it has completed as far as the BDS is conce= rned, * but the drain in this thread can continue immediately after --=20 2.13.6