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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 56504C2D0B1 for ; Tue, 4 Feb 2020 10:35:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37E8821927 for ; Tue, 4 Feb 2020 10:35:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727124AbgBDKfU (ORCPT ); Tue, 4 Feb 2020 05:35:20 -0500 Received: from mx2.suse.de ([195.135.220.15]:49090 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726364AbgBDKfU (ORCPT ); Tue, 4 Feb 2020 05:35:20 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 00132AAC2; Tue, 4 Feb 2020 10:35:17 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Tue, 04 Feb 2020 11:35:16 +0100 From: Roman Penyaev To: =?UTF-8?Q?Max_Neunh=C3=B6ffer?= Cc: Jakub Kicinski , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, LKML , Christopher Kohlhoff , lars@arangodb.com Subject: Re: epoll_wait misses edge-triggered eventfd events: bug in Linux 5.3 and 5.4 In-Reply-To: References: <20200131135730.ezwtgxddjpuczpwy@tux> <20200201121647.62914697@cakuba.hsd1.ca.comcast.net> <20200203151536.caf6n4b2ymvtssmh@tux> <5a16db1f2983ab105b99121ce0737d11@suse.de> Message-ID: X-Sender: rpenyaev@suse.de User-Agent: Roundcube Webmail Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020-02-03 22:03, Max Neunhöffer wrote: > Hi Roman, > > Thanks for your quick response. This sounds fantastic! > > The epollbug.c program was originally written by my colleague Lars > Maier and then modified by me and subsequently by Chris Kohlhoff. Note > that the bugzilla bug report contains altogether three variants which > test epoll_wait/epoll_ctl in three different ways. It might be > sensible to take all three variants for the test suite. I checked 3 variants, they do same things: epoll_ctl() races against epoll_wait(), and this is exactly the bug reproduction, regardless actual read() from a file descriptor or EPOLLET flag set. > I cannot imagine that any of the three authors would object to this, I > definitely do not, the other two are on Cc in this email and can speak > for themselves. I adapted the logic from epollbug.c and included it into epoll_wakeup_test.c test suite, you should have received the email: "[PATCH 3/3] kselftest: introduce new epoll test case". Please, take a look or ask your colleague to take a look. If no objections - then fine, leave as is. Thanks. -- Roman