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=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 DC3AFC4363C for ; Wed, 7 Oct 2020 18:21:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 759A92173E for ; Wed, 7 Oct 2020 18:21:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="a7iDeZjs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727860AbgJGSVd (ORCPT ); Wed, 7 Oct 2020 14:21:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726100AbgJGSVc (ORCPT ); Wed, 7 Oct 2020 14:21:32 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5943BC061755 for ; Wed, 7 Oct 2020 11:21:31 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id d6so1400422plo.13 for ; Wed, 07 Oct 2020 11:21:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=dG6Pgx/Z9y+pOCfqUIFqdfuAZFEij0fF75ctt2BQqBk=; b=a7iDeZjsKaTEY/BiOzObBqqX9n3Dzzfs/KHGqaicIMR3Vbh1OhdAioF5svR2RzoUKd nOsreW5t5/4lueFad8DoK3CGPmzEXTYEy4p9DLX1h3Lzr0AFXS2BEZa3YRX00EAAyEHq XyE19Vebvee8aWMkPoFILYFpR0e3zNEucAAwY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=dG6Pgx/Z9y+pOCfqUIFqdfuAZFEij0fF75ctt2BQqBk=; b=aY0nGb02hwZP1M20N5MYpnLbHY9SOIbYTzHZ1H1jTgnuj19K0LJSACD5L9gLbAWO3M zFL7uRsv0/31iB0SyTLrZyfnQISh4v4xI62qb2U2XDLUrxkIoM+s5QvwQSLYqy7E/FYo Eezzm91e5+GB+ahGjyUvD0NW8/Y9+zCjddmq0X9L+9TViRqaYVvNllUNhTU4r3zK1FTb SNPaOsc5/OxS7uHLVuvVE1NtWad5OmQTHbhLwsub/f6xZYgnMunTiTHEi2Wt7PxwOMSD gzfLsv76s12BdMwciIcz5wVArvCFt4AshMG6L0KSUM5w7e3Lf3cv1tyd38ssQILdGnx/ h/aA== X-Gm-Message-State: AOAM533KvhyBSxJOZu4lS+qIYVel8Mq0xBlrY0g6BMdTCCoiWZtEeWlH Mx22MTKuv6/RVD7LnH4DE23BrA== X-Google-Smtp-Source: ABdhPJwx5SPC2AB77nIV2f5dVxirmq93hteJVobZaULnIUZ810ab0rDWkEpGuoPBMumBkRsJ7ak9GQ== X-Received: by 2002:a17:902:b191:b029:d2:6277:3898 with SMTP id s17-20020a170902b191b02900d262773898mr4105693plr.10.1602094890958; Wed, 07 Oct 2020 11:21:30 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m13sm3299757pjl.45.2020.10.07.11.21.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2020 11:21:29 -0700 (PDT) Date: Wed, 7 Oct 2020 11:21:29 -0700 From: Kees Cook To: Shuah Khan Cc: minyard@acm.org, arnd@arndb.de, gregkh@linuxfoundation.org, openipmi-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Corey Minyard Subject: Re: [PATCH v2 09/11] drivers/char/ipmi: convert stats to use counter_atomic32 Message-ID: <202010071121.1BA120D@keescook> References: <46fcf1d28532868abd1c2dedaab221be56736db9.1602011710.git.skhan@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46fcf1d28532868abd1c2dedaab221be56736db9.1602011710.git.skhan@linuxfoundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 06, 2020 at 02:44:40PM -0600, Shuah Khan wrote: > counter_atomic* is introduced to be used when a variable is used as > a simple counter and doesn't guard object lifetimes. This clearly > differentiates atomic_t usages that guard object lifetimes. > > counter_atomic* variables will wrap around to 0 when it overflows and > should not be used to guard resource lifetimes, device usage and > open counts that control state changes, and pm states. > > atomic_t variables used for stats are atomic counters. Overflow will > wrap around and reset the stats and no change with the conversion. > > Convert them to use counter_atomic32. > > Reviewed-by: Corey Minyard > Signed-off-by: Shuah Khan Reviewed-by: Kees Cook -- Kees Cook