From patchwork Tue May 2 18:41:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 1775995 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=K6dlrP89; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Q9pqg6f42z1ymp for ; Wed, 3 May 2023 04:43:11 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ptuwv-0000Ht-16; Tue, 02 May 2023 14:42:05 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ptuws-0000Gs-RH for qemu-devel@nongnu.org; Tue, 02 May 2023 14:42:02 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ptuwq-0006YA-TB for qemu-devel@nongnu.org; Tue, 02 May 2023 14:42:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683052920; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HCB5geFjokxuVJ1NRiOmPxwOvViDN+Zq0evyFgxcIWc=; b=K6dlrP89Ga+HXpF6xWj02ywfc1eiRS75a5lE0U3ZcUbwlJHOoWMC4zcUpyYGYScovw2o9i K5BKZp8Wv+ulat+CVeOfna0sSs3F2LKgg0/tzrGk1xt17UEXCwxhpyb1gAVT4PRnvuW4b6 LTkHppoNWGKvyKyVB3w1pYntd4o0BMA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-508-3JkK_PPPOfKUtg2xuCnDGA-1; Tue, 02 May 2023 14:41:58 -0400 X-MC-Unique: 3JkK_PPPOfKUtg2xuCnDGA-1 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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6595B87B2A8; Tue, 2 May 2023 18:41:57 +0000 (UTC) Received: from localhost (unknown [10.39.192.230]) by smtp.corp.redhat.com (Postfix) with ESMTP id 976562166B26; Tue, 2 May 2023 18:41:41 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Fam Zheng , Paolo Bonzini , Stefan Hajnoczi , qemu-block@nongnu.org Subject: [PATCH 2/2] tested: add test for nested aio_poll() in poll handlers Date: Tue, 2 May 2023 14:41:34 -0400 Message-Id: <20230502184134.534703-3-stefanha@redhat.com> In-Reply-To: <20230502184134.534703-1-stefanha@redhat.com> References: <20230502184134.534703-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.171, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Signed-off-by: Stefan Hajnoczi --- tests/unit/test-nested-aio-poll.c | 130 ++++++++++++++++++++++++++++++ tests/unit/meson.build | 1 + 2 files changed, 131 insertions(+) create mode 100644 tests/unit/test-nested-aio-poll.c diff --git a/tests/unit/test-nested-aio-poll.c b/tests/unit/test-nested-aio-poll.c new file mode 100644 index 0000000000..9bbe18b839 --- /dev/null +++ b/tests/unit/test-nested-aio-poll.c @@ -0,0 +1,130 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Test that poll handlers are not re-entrant in nested aio_poll() + * + * Copyright Red Hat + * + * Poll handlers are usually level-triggered. That means they continue firing + * until the condition is reset (e.g. a virtqueue becomes empty). If a poll + * handler calls nested aio_poll() before the condition is reset, then infinite + * recursion occurs. + * + * aio_poll() is supposed to prevent this by disabling poll handlers in nested + * aio_poll() calls. This test case checks that this is indeed what happens. + */ +#include "qemu/osdep.h" +#include "block/aio.h" +#include "qapi/error.h" + +typedef struct { + AioContext *ctx; + + /* This is the EventNotifier that drives the test */ + EventNotifier poll_notifier; + + /* This EventNotifier is only used to wake aio_poll() */ + EventNotifier dummy_notifier; + + bool nested; +} TestData; + +static void io_read(EventNotifier *notifier) +{ + fprintf(stderr, "%s %p\n", __func__, notifier); + event_notifier_test_and_clear(notifier); +} + +static bool io_poll_true(void *opaque) +{ + fprintf(stderr, "%s %p\n", __func__, opaque); + return true; +} + +static bool io_poll_false(void *opaque) +{ + fprintf(stderr, "%s %p\n", __func__, opaque); + return false; +} + +static void io_poll_ready(EventNotifier *notifier) +{ + TestData *td = container_of(notifier, TestData, poll_notifier); + + fprintf(stderr, "> %s\n", __func__); + + g_assert(!td->nested); + td->nested = true; + + /* Wake the following nested aio_poll() call */ + event_notifier_set(&td->dummy_notifier); + + /* This nested event loop must not call io_poll()/io_poll_ready() */ + g_assert(aio_poll(td->ctx, true)); + + td->nested = false; + + fprintf(stderr, "< %s\n", __func__); +} + +/* dummy_notifier never triggers */ +static void io_poll_never_ready(EventNotifier *notifier) +{ + g_assert_not_reached(); +} + +static void test(void) +{ + TestData td = { + .ctx = aio_context_new(&error_abort), + }; + + qemu_set_current_aio_context(td.ctx); + + /* Enable polling */ + aio_context_set_poll_params(td.ctx, 1000000, 2, 2, &error_abort); + + /* + * The GSource is unused but this has the side-effect of changing the fdmon + * that AioContext uses. + */ + aio_get_g_source(td.ctx); + + /* Make the event notifier active (set) right away */ + event_notifier_init(&td.poll_notifier, 1); + aio_set_event_notifier(td.ctx, &td.poll_notifier, false, + io_read, io_poll_true, io_poll_ready); + + /* This event notifier will be used later */ + event_notifier_init(&td.dummy_notifier, 0); + aio_set_event_notifier(td.ctx, &td.dummy_notifier, false, + io_read, io_poll_false, io_poll_never_ready); + + /* Consume aio_notify() */ + g_assert(!aio_poll(td.ctx, false)); + + /* + * Run the io_read() handler. This has the side-effect of activating + * polling in future aio_poll() calls. + */ + g_assert(aio_poll(td.ctx, true)); + + /* The second time around the io_poll()/io_poll_ready() handler runs */ + g_assert(aio_poll(td.ctx, true)); + + /* Run io_poll()/io_poll_ready() one more time to show it keeps working */ + g_assert(aio_poll(td.ctx, true)); + + aio_set_event_notifier(td.ctx, &td.dummy_notifier, false, + NULL, NULL, NULL); + aio_set_event_notifier(td.ctx, &td.poll_notifier, false, NULL, NULL, NULL); + event_notifier_cleanup(&td.dummy_notifier); + event_notifier_cleanup(&td.poll_notifier); + aio_context_unref(td.ctx); +} + +int main(int argc, char **argv) +{ + g_test_init(&argc, &argv, NULL); + g_test_add_func("/nested-aio-poll", test); + return g_test_run(); +} diff --git a/tests/unit/meson.build b/tests/unit/meson.build index 3bc78d8660..a314f82baa 100644 --- a/tests/unit/meson.build +++ b/tests/unit/meson.build @@ -67,6 +67,7 @@ if have_block 'test-coroutine': [testblock], 'test-aio': [testblock], 'test-aio-multithread': [testblock], + 'test-nested-aio-poll': [testblock], 'test-throttle': [testblock], 'test-thread-pool': [testblock], 'test-hbitmap': [testblock],