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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 7863AC28CC3 for ; Thu, 30 May 2019 15:48:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5268525D0B for ; Thu, 30 May 2019 15:48:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OSlz9oSP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbfE3PsY (ORCPT ); Thu, 30 May 2019 11:48:24 -0400 Received: from mail-io1-f68.google.com ([209.85.166.68]:44771 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbfE3PsY (ORCPT ); Thu, 30 May 2019 11:48:24 -0400 Received: by mail-io1-f68.google.com with SMTP id f22so5429881iol.11; Thu, 30 May 2019 08:48:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=3olQvP45h39vAZdvBqNRdDIW/OYVYSxl9B+1Z8goMDM=; b=OSlz9oSP57X73P9v8T1SGzdHu+TSRK0BQfHQ52vHbEKVUXF1//MODLfSiNzRLny+3w rleqXIdXCv5T7ezYqzKxFLxTnkfIlrGvuW1dB1cp1I7dk0q1VYaM0uiZzzjbCiCOeWI1 U03eULXCOm5eGLcqRwiRqk4gGdHjoSYCMXAU1NgyUlCVaXVZ5QwTXJoJnErzm1hbpCtN eMLG/tSelV6Xkn/jzRCBsAeXCK7On/ITxYk/U/j/hpGMiwH+kqIsxQn+d58L7pwCPLSb RFBx2v/K8WSSuhU0Dx32A4ha5ulOFuxygaptgd3Dwoziw1QyfU3cJlVzVZqPYrfuTyQP M6gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=3olQvP45h39vAZdvBqNRdDIW/OYVYSxl9B+1Z8goMDM=; b=JHnGNIVGudtTrDWDnA7CFDQCrDQAh75hIJfyuGgAk/xTv53JjZ/DWLQRE2UMw6vfzH FConwWdLVuLMnN8AvFcExXT5gqmDeknEFWtPhVYpLReGDTK9fX7xmo2NE5x/9H6IK6EZ UiClImY58UKpVRiLOB0sfzr443M6ZjXb+ZLyit8NE+pyoqieWGERtrDw/VOZ8AHJ5BTY bxbn67QycyB+fSNhuoaoWyMj617jmrjsLv1hby54uKEtAZ8xuG+FTHxhSQZ0Y/p3m8/y pqUA/7awtkPICzsy1HvmTzLmuqR+CoIoesrNE8b8ocZ+HSPt+hFSqV+xDhNveloIOZzC Hoxw== X-Gm-Message-State: APjAAAXJXybq2HoscdvpX50AgB+skq4XNxBeUpDIVbsrJKfZreD/EdlB 9lJIziu4cI2a26ffzPgt2Iqr/XTPuOETicZqlU4= X-Google-Smtp-Source: APXvYqzxYpkdxpKc35hfYTazS7WePXHFReDy++1I+d8I5tTo+pAFe1tbs+Nn+yj5IJpa57U4mzBaSaT7/6aUGiL3P4U= X-Received: by 2002:a6b:6217:: with SMTP id f23mr3170264iog.110.1559231303258; Thu, 30 May 2019 08:48:23 -0700 (PDT) MIME-Version: 1.0 References: <20190522032144.10995-1-deepa.kernel@gmail.com> <20190529161157.GA27659@redhat.com> <87woi8rt96.fsf@xmission.com> <871s0grlzo.fsf@xmission.com> In-Reply-To: <871s0grlzo.fsf@xmission.com> From: Deepa Dinamani Date: Thu, 30 May 2019 08:48:12 -0700 Message-ID: Subject: Re: pselect/etc semantics To: "Eric W. Biederman" Cc: Oleg Nesterov , Al Viro , Linus Torvalds , Linux Kernel Mailing List , Andrew Morton , Arnd Bergmann , dbueso@suse.de, axboe@kernel.dk, Davidlohr Bueso , Eric Wong , Jason Baron , Linux FS-devel Mailing List , linux-aio , Omar Kilani , Thomas Gleixner , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 30, 2019, at 8:38 AM, Eric W. Biederman wr= ote: > > ebiederm@xmission.com (Eric W. Biederman) writes: > >> Which means I believe we have a semantically valid change in behavior >> that is causing a regression. > > I haven't made a survey of all of the functions yet but > fucntions return -ENORESTARTNOHAND will never return -EINTR and are > immune from this problem. > > AKA pselect is fine. While epoll_pwait can be affected. This was my understanding as well. > Has anyone contacted Omar Kilani to see if that is his issue? > https://lore.kernel.org/lkml/CA+8F9hicnF=3DkvjXPZFQy=3DPa2HJUS3JS+G9VswFH= NQQynPMHGVQ@mail.gmail.com/ Omar was cc-ed when this regression was reported. I did cc him on fix and asked if he could try it. We have not heard from him. > So far the only regression report I am seeing is from Eric Wong. > AKA https://lore.kernel.org/lkml/20190501021405.hfvd7ps623liu25i@dcvr/ > Are there any others? How did we get to be talking about more > than just epoll_pwait? This is the only report that I know of. I=E2=80=99m not sure why people started talking about pselect. I was also confused why instead of reviewing the patch and discussing the fix, we ended up talking about how to simplify the code. We have deviated much from what should have been a code review. -Deepa