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 5045EFC6196 for ; Fri, 8 Nov 2019 21:36:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2281320650 for ; Fri, 8 Nov 2019 21:36:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573249006; bh=aiHMdEMJOgAa6jrM3jbVr8IRnFbQkF1HPb45tscKBaQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=yYWjaqOixp8GUlOUzwnRJDRsrXLVQy1wgvUuosaMjPCW+AQK77ajYbRJu6lLYfXXZ j175AZML13thfp45GItFG7U7H2VhxrrSxrlFK/jnRto9/YC0JnAWQgC3k0bv+q4TAD 83gHrYC/P5PQAd3omVfzspDznjQCIwyiXbL/NsQo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731882AbfKHVgp (ORCPT ); Fri, 8 Nov 2019 16:36:45 -0500 Received: from mail-lj1-f178.google.com ([209.85.208.178]:45846 "EHLO mail-lj1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730989AbfKHVgp (ORCPT ); Fri, 8 Nov 2019 16:36:45 -0500 Received: by mail-lj1-f178.google.com with SMTP id n21so7676427ljg.12 for ; Fri, 08 Nov 2019 13:36:43 -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=qGYbfXBmYeGO7pa06B9v9RYZuC6G4mksi25tARbE4oY=; b=D2lIv3jCmGx6XX86kRru64oEZZHnbWw2knlo1We7LolVbJbNK9HgSHPqCuNFkLo8ad GU8k1DTmDoi/kms3XxcfX7lhY59TGnHP8CiCPpdo/DYtNT8a4RPLc9sR5QaxINzKAI91 MruliR/YTKfAHzSlhF17f4O8c+PUKsS3yl0wk= 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=qGYbfXBmYeGO7pa06B9v9RYZuC6G4mksi25tARbE4oY=; b=mgAk1SvyD5oENW9XxRMeMYdlHcMCUYMNYejvYdi4WZQ8VHOpJLkCfU2psmFRJAmrZG 4kaj/eDmRz/O3SCU9rcVrgzly6HXOugdWYnIvCg46HlvUWJCJBTfouMn2Vd0jemzUKjL Lr98YPcF4tqbckhkh3fob89v4gpm8uThO4bu4059H0JR6LY2gUUtO1/TqgtKijF8NV6D 5/Tcsvbygk8DtFNqI6NkFkBWonZR6PtoQZBdgWg1J+/IuHxHDB0SuBGE4CkbZ9uGDHaD nPlsRzUv5Luc7iH8WUejQsM5ytEe9w3FnO4VXDld3MzwR8gSr++dMCIleSqnIiAOU3H7 8c1Q== X-Gm-Message-State: APjAAAXw8hULvSrNdZSNNNxBJquupHXrag3DGa+4R1Ly0NEh5oDfuF9W /rTqQbPMVoY7GGjlbTtIS6d78KNipms= X-Google-Smtp-Source: APXvYqxSc/cT54cDcmf/IxrYlT2MVG1eDPBlHjk7jvk/UeH0ApO6KpKnHarAMufEs0+7eHLWzpEgIw== X-Received: by 2002:a05:651c:313:: with SMTP id a19mr769805ljp.199.1573249002483; Fri, 08 Nov 2019 13:36:42 -0800 (PST) Received: from mail-lj1-f180.google.com (mail-lj1-f180.google.com. [209.85.208.180]) by smtp.gmail.com with ESMTPSA id c22sm3632640lfj.28.2019.11.08.13.36.40 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 Nov 2019 13:36:41 -0800 (PST) Received: by mail-lj1-f180.google.com with SMTP id l21so371314ljg.4 for ; Fri, 08 Nov 2019 13:36:40 -0800 (PST) X-Received: by 2002:a05:651c:331:: with SMTP id b17mr8336920ljp.133.1573249000556; Fri, 08 Nov 2019 13:36:40 -0800 (PST) MIME-Version: 1.0 References: <000000000000c422a80596d595ee@google.com> <6bddae34-93df-6820-0390-ac18dcbf0927@gmail.com> In-Reply-To: From: Linus Torvalds Date: Fri, 8 Nov 2019 13:36:23 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: KCSAN: data-race in __alloc_file / __alloc_file To: Eric Dumazet Cc: Eric Dumazet , syzbot , Marco Elver , linux-fsdevel , Linux Kernel Mailing List , syzkaller-bugs , Al Viro 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, Nov 8, 2019 at 12:53 PM Eric Dumazet wrote: > > per cpu SNMP counters mostly, with no IRQ safety requirements. > > Note that this could be implemented using local{64}_add() on arches like x86_64, > while others might have to fallback to WRITE_ONCE(variable, variable + add) raw_cpu_add()? We already use those for vm_counters where we intentionally accept races. Linus