From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 365EFC2BA1A for ; Tue, 7 Apr 2020 03:11:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E856F206B8 for ; Tue, 7 Apr 2020 03:11:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XRvPCaIC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E856F206B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 98E398E008F; Mon, 6 Apr 2020 23:11:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 966F58E0062; Mon, 6 Apr 2020 23:11:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 854B48E008F; Mon, 6 Apr 2020 23:11:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0235.hostedemail.com [216.40.44.235]) by kanga.kvack.org (Postfix) with ESMTP id 6C2CD8E0062 for ; Mon, 6 Apr 2020 23:11:22 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3E6AF8018F1B for ; Tue, 7 Apr 2020 03:11:22 +0000 (UTC) X-FDA: 76679583204.04.rule32_be9c370a1402 X-HE-Tag: rule32_be9c370a1402 X-Filterd-Recvd-Size: 4413 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:11:21 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B7FC620781; Tue, 7 Apr 2020 03:11:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586229081; bh=CIfRJGo+LDjKX8BmzTKvYHqRxJAS0/F1kulBnQo+1fA=; h=Date:From:To:Subject:In-Reply-To:From; b=XRvPCaICwnYWTRfue84kT5Qz/Yk+zQ2HCZqBss1cCE3op7l2JE1CICASqopNWrHNh Tjd2CbcmSENGCS2rDqHl7dhbD2uWSTw3Z9lgIUVwi0/inJzI9tJtHDgZkTBaZUgzd9 bj18OmBntTc2D9Xizf1eBFZTACxwGDTfOP87E+0Q= Date: Mon, 06 Apr 2020 20:11:20 -0700 From: Andrew Morton To: akpm@linux-foundation.org, chris.kohlhoff@clearpool.io, dbueso@suse.de, jbaron@akamai.com, jes.sorensen@gmail.com, kuba@kernel.org, linux-mm@kvack.org, max@arangodb.com, mm-commits@vger.kernel.org, rpenyaev@suse.de, torvalds@linux-foundation.org Subject: [patch 137/166] kselftest: introduce new epoll test case Message-ID: <20200407031120.SCqdQY1nS%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Roman Penyaev Subject: kselftest: introduce new epoll test case This testcase repeats epollbug.c from the bug: https://bugzilla.kernel.org/show_bug.cgi?id=205933 What it tests? It tests the race between epoll_ctl() and epoll_wait(). New event mask passed to epoll_ctl() triggers wake up, which can be missed because of the bug described in the link. Reproduction is 100%, so easy to fix. Kudos, Max, for wonderful test case. Link: http://lkml.kernel.org/r/20200214170211.561524-2-rpenyaev@suse.de Signed-off-by: Roman Penyaev Cc: Max Neunhoeffer Cc: Jakub Kicinski Cc: Christopher Kohlhoff Cc: Davidlohr Bueso Cc: Jason Baron Cc: Jes Sorensen Signed-off-by: Andrew Morton --- tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c | 67 +++++++++- 1 file changed, 66 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c~kselftest-introduce-new-epoll-test-case +++ a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c @@ -7,13 +7,14 @@ #include #include #include +#include #include "../../kselftest_harness.h" struct epoll_mtcontext { int efd[3]; int sfd[4]; - int count; + volatile int count; pthread_t main; pthread_t waiter; @@ -3071,4 +3072,68 @@ TEST(epoll58) close(ctx.sfd[3]); } +static void *epoll59_thread(void *ctx_) +{ + struct epoll_mtcontext *ctx = ctx_; + struct epoll_event e; + int i; + + for (i = 0; i < 100000; i++) { + while (ctx->count == 0) + ; + + e.events = EPOLLIN | EPOLLERR | EPOLLET; + epoll_ctl(ctx->efd[0], EPOLL_CTL_MOD, ctx->sfd[0], &e); + ctx->count = 0; + } + + return NULL; +} + +/* + * t0 + * (p) \ + * e0 + * (et) / + * e0 + * + * Based on https://bugzilla.kernel.org/show_bug.cgi?id=205933 + */ +TEST(epoll59) +{ + pthread_t emitter; + struct pollfd pfd; + struct epoll_event e; + struct epoll_mtcontext ctx = { 0 }; + int i, ret; + + signal(SIGUSR1, signal_handler); + + ctx.efd[0] = epoll_create1(0); + ASSERT_GE(ctx.efd[0], 0); + + ctx.sfd[0] = eventfd(1, 0); + ASSERT_GE(ctx.sfd[0], 0); + + e.events = EPOLLIN | EPOLLERR | EPOLLET; + ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0); + + ASSERT_EQ(pthread_create(&emitter, NULL, epoll59_thread, &ctx), 0); + + for (i = 0; i < 100000; i++) { + ret = epoll_wait(ctx.efd[0], &e, 1, 1000); + ASSERT_GT(ret, 0); + + while (ctx.count != 0) + ; + ctx.count = 1; + } + if (pthread_tryjoin_np(emitter, NULL) < 0) { + pthread_kill(emitter, SIGUSR1); + pthread_join(emitter, NULL); + } + close(ctx.efd[0]); + close(ctx.sfd[0]); +} + TEST_HARNESS_MAIN _