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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 EA6CFC2D0BF for ; Thu, 5 Dec 2019 17:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C46D42464D for ; Thu, 5 Dec 2019 17:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575566718; bh=Rw7OSMPf9yit/kp3KVKphhbKGqVjIJjjc9QupnBWMos=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=qgLipkknv29K0oRY/2O2DjqyuHoXaVACZnABz6MAgU4VHjy58FNn6SyKNsovVbETS Sx1UbDsSfBDiBQtJgNWpnFbN8B6s4Y76NJTSiVWKT/fOYtZrZo9YWEuhQdBPJRVFzb K0KMvnylffcPTiksxPaGd0JowiXlt49Md3xOXUv4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730115AbfLERZP (ORCPT ); Thu, 5 Dec 2019 12:25:15 -0500 Received: from mail-lf1-f68.google.com ([209.85.167.68]:33552 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729993AbfLERZM (ORCPT ); Thu, 5 Dec 2019 12:25:12 -0500 Received: by mail-lf1-f68.google.com with SMTP id n25so3140164lfl.0 for ; Thu, 05 Dec 2019 09:25:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wcGyAgv2BiiKMB4o1JPjh3c4/KLE1QL1Cs5ZGEHCDIc=; b=h8R8qn2a8yMheUZxZicjSxy1mjJzLS/SXEZWNWhN2n29VR1l3aKAlm1cuqN3fZyRfk 7RiJ2tHBwlnu/dxOScE0uVy3iZQZ7SYeh67Cd1w1vNd2lAU44JJHrRfgT90jo1Vxdgk6 hfczULjbW6MoOj6k0umoQaFr+3JFVFJeh4/gg= 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=wcGyAgv2BiiKMB4o1JPjh3c4/KLE1QL1Cs5ZGEHCDIc=; b=NmC1/pLwOzsv6N3qZe3eLFGiXXVaa1rfoAzlruFTY6kuFCxMVXqevwK08+rCtXOzei 8AXiU1oX+sov5LrahoMRoaddCxX8DLh55HoZ3wE1RXK1pLAZdyfoAYZKYbE7Psl5rzF9 O6fMqzU+2vH8vX+22VkPcNEvmBozx8Auilj/C7SVLC5XHhHzmo7Lp9ExfdXCYDCVz0w1 iJ7PX9+aOjlo6/WZDradJGDex1ABZAX/2VjlkIPbRkk1ysIHDTCq8pTh3DnGxgS5YRJR 2k/11KQn8Iso6ik5f0KvTskrC2dv2we3uzvP/8tcWpPSYU9xqtTRCosvU0gjxI0LX9Wu umZg== X-Gm-Message-State: APjAAAUV7NHkYYrWBDBw+d90aaxJfRU2CmRj0jbPxTAE6EVqxdrl/QGp YovXysi3xQvPxEp4w7Q438CQ4AoJ+GA= X-Google-Smtp-Source: APXvYqyRe+gVq2lo/kzn4VT7OqMYvagLY64BvahHAwnMihI/mAloAShbJ4BJoMUhXfRZf0oj62I1Pg== X-Received: by 2002:ac2:5216:: with SMTP id a22mr5870101lfl.18.1575566709561; Thu, 05 Dec 2019 09:25:09 -0800 (PST) Received: from mail-lj1-f174.google.com (mail-lj1-f174.google.com. [209.85.208.174]) by smtp.gmail.com with ESMTPSA id w71sm6136706lff.0.2019.12.05.09.25.08 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Dec 2019 09:25:08 -0800 (PST) Received: by mail-lj1-f174.google.com with SMTP id 21so4547249ljr.0 for ; Thu, 05 Dec 2019 09:25:08 -0800 (PST) X-Received: by 2002:a2e:91cb:: with SMTP id u11mr3763207ljg.82.1575566707941; Thu, 05 Dec 2019 09:25:07 -0800 (PST) MIME-Version: 1.0 References: <31452.1574721589@warthog.procyon.org.uk> <20191205125826.GK2734@twin.jikos.cz> <1593.1575554217@warthog.procyon.org.uk> In-Reply-To: From: Linus Torvalds Date: Thu, 5 Dec 2019 09:24:51 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [GIT PULL] pipe: Notification queue preparation To: David Howells Cc: David Sterba , Rasmus Villemoes , Greg Kroah-Hartman , Peter Zijlstra , raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-block , LSM List , linux-fsdevel , Linux API , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Dec 5, 2019 at 9:12 AM Linus Torvalds wrote: > > It would be interesting to hear if somebody else is waiting on the > read side too. Looking once more at that commit, I find at least one bug, but I'm pretty sure that's not the cause of this problem. DavidH, watch out for things like this: - for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) + for (idx = tail; idx < head && rem < len; idx++) which is a completely buggy conversion. You can't compare tail and head with an inequality, it gets the wraparound case wrong. But I found only one of those, and it's fuse-specific, plus the overflow would take a long time to trigger, so I'm pretty sure this isn't what DavidS is reporting. Linus