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=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=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 41BD4C3F2D1 for ; Thu, 5 Mar 2020 19:54:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 165A12072A for ; Thu, 5 Mar 2020 19:54:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ixCHyDIt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726083AbgCETyQ (ORCPT ); Thu, 5 Mar 2020 14:54:16 -0500 Received: from mail-oi1-f193.google.com ([209.85.167.193]:33758 "EHLO mail-oi1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725963AbgCETyP (ORCPT ); Thu, 5 Mar 2020 14:54:15 -0500 Received: by mail-oi1-f193.google.com with SMTP id q81so122895oig.0; Thu, 05 Mar 2020 11:54:13 -0800 (PST) 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; bh=ZqWlHzyhCikKFonKGJ0xmTAmithkM6Eizd/S+WaA0WU=; b=ixCHyDItow1nSYhZ6w6LHPnqSFv2mlCCjNfKPn1J861HUMBgqH1tLJuonJWQSo/7ZR MgPkgYi9rYzeqjxhCTu5yjXwhSWH9umr6QxK52m5BltUuaR2D6D6VOFtYnY9BsOlF6CJ kwNr/BRIQL6zFwA6CcP7Qh+o5EflMWMRxK3UpsNba7U/GnBT3UO4mUNsPlcVYE+nfXb8 ikXqFfz7504DcINa4WNOtqiWs4TCiD+mxtUzpfjyLfLrLtqVHIeEzJ9VQbbw1DGdKlRz HIqWZn6b+XacjUYvKPryHEDuUFzYJqkdL4/Tk4uODbXej19cR94tTqLb3E58TLr3x0l8 hhnw== 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; bh=ZqWlHzyhCikKFonKGJ0xmTAmithkM6Eizd/S+WaA0WU=; b=Q+VXem1Lp/NyJ/h4jHV2UyE06qF9we6q3BVNwp8w/gBJJS2FB9zNM8CYF69Diu9+TG 21x2P4Dan1D6wh2ATskQDM74baG6GTqDakjCQV/IgJ0qkN5l8B7wLvL+Jwvvopg7uG8h gycQgCOVPkWR1xTnV7ptdeKGNYfNQPU3u4MIHkLggMI3qB3Cm51bXxRk6SHysR9AFtRt UwOaQaTZspCBrzCesX5E6gn94ZpEQ1RwgVhHJGFB9kimU9TxZQNdQrSgtTZiERX3UeN6 Q6bAX+G212OLioZlcmczF91ijSi++AxfugAaVqdt2m5GdtkK7C5r0ZRqbQUGi0eJ0NAz qXqg== X-Gm-Message-State: ANhLgQ3DSLQZ2HkwAj/wKelB6G8UtGI4A95HN7Sz3mdMvEFt58mIDfni DTd2KPPT0hesf4Z2YZWtO9RrH9bh9/VBF76Y7+g= X-Google-Smtp-Source: ADFU+vsFgMEhG5cWn4vZxf3o8RE62gjhlPqvGlsp6zUxbicUiaEpyE4+4xPyUpLOwe8dbk+NW/AFjlioIwk110UMLlY= X-Received: by 2002:aca:170c:: with SMTP id j12mr83643oii.50.1583438052868; Thu, 05 Mar 2020 11:54:12 -0800 (PST) MIME-Version: 1.0 References: <20200214154854.6746-1-sashal@kernel.org> <20200214154854.6746-542-sashal@kernel.org> <20200218182041.GB24185@bombadil.infradead.org> <20200218223325.GA143300@gmail.com> In-Reply-To: From: Andrei Vagin Date: Thu, 5 Mar 2020 11:54:01 -0800 Message-ID: Subject: Re: [PATCH AUTOSEL 5.5 542/542] pipe: use exclusive waits when reading or writing To: Linus Torvalds Cc: Matthew Wilcox , LKML , Sasha Levin , stable , Josh Triplett , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 5, 2020 at 10:41 AM Linus Torvalds wrote: > > On Thu, Mar 5, 2020 at 12:20 PM Andrei Vagin wrote: > > > > After this change, one more criu test became flaky. This is due to one > > of corner cases, so I am not sure that we need to fix something in the > > kernel. I have fixed this issue in the test. I am not sure that this > > will affect any real applications. > > It's an interesting test-case, but it's really not doing anything you > should rely on. I'm agree with this. > But if CRIU itself depends on this behavior (rather than just a test), > then I guess we need to. > > So is it just a test-case, or does CRIU itself depend on that "reads > get full buffers"? As mentioned, that really _is_ fundamentally broken > if there is any chance of signals.. No, it doesn't. I'm agree that we can wait an report from a real app. Thanks! Andrei