From nobody Wed Nov 5 12:20:51 2025 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 (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1537460932991721.5292530220472; Thu, 20 Sep 2018 09:28:52 -0700 (PDT) Received: from localhost ([::1]:51992 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g31ot-00045d-PF for importer@patchew.org; Thu, 20 Sep 2018 12:28:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g31hA-00051j-Us for qemu-devel@nongnu.org; Thu, 20 Sep 2018 12:20:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g31h9-00063t-By for qemu-devel@nongnu.org; Thu, 20 Sep 2018 12:20:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25242) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g31h4-0005sY-B4; Thu, 20 Sep 2018 12:20:42 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AAB8D81DE3; Thu, 20 Sep 2018 16:20:41 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-116-231.ams2.redhat.com [10.36.116.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id D46EE85A33; Thu, 20 Sep 2018 16:20:39 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Thu, 20 Sep 2018 18:19:53 +0200 Message-Id: <20180920161958.27453-15-kwolf@redhat.com> In-Reply-To: <20180920161958.27453-1-kwolf@redhat.com> References: <20180920161958.27453-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 20 Sep 2018 16:20:41 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 14/19] 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, jsnow@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 Reviewed-by: Fam Zheng --- 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 c3c17b9ff7..e105c0ae84 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