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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 E9DA6C433E2 for ; Fri, 17 Jul 2020 06:02:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE91E2070A for ; Fri, 17 Jul 2020 06:02:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VbOvQYl/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726250AbgGQGCs (ORCPT ); Fri, 17 Jul 2020 02:02:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726083AbgGQGCs (ORCPT ); Fri, 17 Jul 2020 02:02:48 -0400 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAC71C061755; Thu, 16 Jul 2020 23:02:47 -0700 (PDT) Received: by mail-il1-x143.google.com with SMTP id k6so6404625ili.6; Thu, 16 Jul 2020 23:02:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc; bh=ve/cmXtNUOqHiayEYTadiiBcyTXVbObeiw7WV4ExN98=; b=VbOvQYl/a15OZU3ZulHv64cd9EjeIZTIQ/l9Ih0MNzUws8Gr+INBxuM3rcBDbbG5fU kOCg2WnqrEiOr6T5HWD6fAOmYMd/uciZ+ubDNcXEAdl5h3u8y7T96tvNoduqGPicJIEV /T0JCyOpGz6pUVf+/7BdV4eovntNshzSNJAvE6LFZcFnqjF6n7P9uey7KPe5TVPHDMpa dq9CegXIHYLPQqdHr7U1o99vB6Iz50iajX1UC/lFemk/k0hMbGSm6FBFTbqUMwDZaqhf gM1vjMH6OPNg0olrZ4tL9Y1Ob5V6+WAPZOSGryvEuQTG9XNZtb28RxolBMgKwj1wN0EA aVMQ== 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:reply-to :from:date:message-id:subject:to:cc; bh=ve/cmXtNUOqHiayEYTadiiBcyTXVbObeiw7WV4ExN98=; b=Rpiz9ZGhsWeyLCpy9gYYNAGEEs0wAR53mDJ4AvFXQihNvddyYkOuk83yFpXhyQ0EvI SxtYDC8gcFn+ThgFwl7JVmdMtBSu5OLZ7C2b3Z8TZU0qmxZ356ddHyUgOGsoBOvOVikW RrSegGGCQTkpPOH9f7ve5pSJnkribnlmlWWyOquxpVjuzIuYgVUh0XCdgu9DePPGX8t/ /Q+AK3a9oWjt0lYRGzvAwEcAx69qjV1XyEvW+o4SugmSkdI5fCK1tCT3FpqDx1VbZR4Z fWeMu2BABJjXGMVQRKlx1KCD5I62F96NA1UyDvmmlZYPSrYW8HtMykO/Df3ttcKTKivT cTUA== X-Gm-Message-State: AOAM533LGvVXEWcQG47b1EWtV0wWdEQtjvPj/LsEoNryxR1cXyTD8pGq VfTekvZf+kUcMoqFdq9qeoWlFOtuKaoqVdu57Mk= X-Google-Smtp-Source: ABdhPJxw89TDMcyDoUVy003U8UgoW1M2CjP36Z5/idIUBu7FhV64fYfsvsAeNagcVB2rNTRHLStu90ucqP2U2eQU/54= X-Received: by 2002:a92:5fc9:: with SMTP id i70mr8774183ill.176.1594965767253; Thu, 16 Jul 2020 23:02:47 -0700 (PDT) MIME-Version: 1.0 References: <20200717050510.95832-1-ebiggers@kernel.org> In-Reply-To: <20200717050510.95832-1-ebiggers@kernel.org> Reply-To: sedat.dilek@gmail.com From: Sedat Dilek Date: Fri, 17 Jul 2020 08:02:36 +0200 Message-ID: Subject: Re: [PATCH v2] fs/direct-io: fix one-time init of ->s_dio_done_wq To: Eric Biggers Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org 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 Fri, Jul 17, 2020 at 7:08 AM Eric Biggers wrote: > - The preliminary checks for sb->s_dio_done_wq are a data race, since > they do a plain load of a concurrently modified variable. According > to the C standard, this undefined behavior. In practice, the kernel > does sometimes makes assumptions about data races might be okay in Some small typos: ...this *is* undefined behavior... ...does sometimes make* assumptions about... - Sedat -