From nobody Tue May 7 01:32:28 2024 Delivered-To: importer@patchew.org Received-SPF: temperror (zoho.com: Error in retrieving data from DNS) 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=temperror (zoho.com: Error in retrieving data from DNS) 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 1509995409989339.5064362115796; Mon, 6 Nov 2017 11:10:09 -0800 (PST) Received: from localhost ([::1]:49868 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBmmH-00070y-O0 for importer@patchew.org; Mon, 06 Nov 2017 14:09:45 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49292) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBmfS-0001Ii-Pc for qemu-devel@nongnu.org; Mon, 06 Nov 2017 14:02:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eBmfO-0000BW-Sm for qemu-devel@nongnu.org; Mon, 06 Nov 2017 14:02:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48624) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eBmfO-0000Au-Mp for qemu-devel@nongnu.org; Mon, 06 Nov 2017 14:02:38 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7D2637F7A2 for ; Mon, 6 Nov 2017 19:02:37 +0000 (UTC) Received: from localhost (unknown [10.36.118.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 938DE60C94; Mon, 6 Nov 2017 19:02:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7D2637F7A2 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=stefanha@redhat.com From: Stefan Hajnoczi To: Date: Mon, 6 Nov 2017 19:02:33 +0000 Message-Id: <20171106190233.1175-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 06 Nov 2017 19:02:37 +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 for-2.11] tests-aio-multithread: fix /aio/multi/schedule race condition 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: Paolo Bonzini , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_6 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" test_multi_co_schedule_entry() set to_schedule[id] in the final loop iteration before terminating the coroutine. There is a race condition where the main thread attempts to enter the terminating or terminated coroutine when signalling coroutines to stop: atomic_mb_set(&now_stopping, true); for (i =3D 0; i < NUM_CONTEXTS; i++) { ctx_run(i, finish_cb, NULL); <--- enters dead coroutine! to_schedule[i] =3D NULL; } Make sure only to set to_schedule[id] if this coroutine really needs to be scheduled! Reported-by: "R.Nageswara Sastry" Signed-off-by: Stefan Hajnoczi Reviewed-by: Paolo Bonzini --- This patch is appropriate for the QEMU 2.11 release to eliminate spurious test failures. tests/test-aio-multithread.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c index 549d784915..d396185972 100644 --- a/tests/test-aio-multithread.c +++ b/tests/test-aio-multithread.c @@ -144,17 +144,16 @@ static void finish_cb(void *opaque) static coroutine_fn void test_multi_co_schedule_entry(void *opaque) { g_assert(to_schedule[id] =3D=3D NULL); - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); =20 while (!atomic_mb_read(&now_stopping)) { int n; =20 n =3D g_test_rand_int_range(0, NUM_CONTEXTS); schedule_next(n); + + atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); qemu_coroutine_yield(); - g_assert(to_schedule[id] =3D=3D NULL); - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); } } =20 --=20 2.13.6