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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 88D7CC74A5B for ; Thu, 11 Jul 2019 16:35:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 601C020872 for ; Thu, 11 Jul 2019 16:35:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BcgcIoO8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728777AbfGKQfu (ORCPT ); Thu, 11 Jul 2019 12:35:50 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:40031 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726213AbfGKQfu (ORCPT ); Thu, 11 Jul 2019 12:35:50 -0400 Received: by mail-pg1-f195.google.com with SMTP id w10so3197371pgj.7; Thu, 11 Jul 2019 09:35:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=MmkG53WQLXsnChwuW4VZaCFghSpsaEReR7YJG6XS3wY=; b=BcgcIoO8JWuECr/LI3atzQ4qxt5OBmIaOr0AK+el9EA3EwjCtUKJeEJJMz56x6JCEc 9RwB/rq61Hn0aUG50lVV0QnO1bj+XHfUbDFoFhwT1uFEjMaZCyq15Z7lRwifB1sJX2QJ kTOLQL38vSoh8eB+AE4q+dzITIvB10BnRneK7HpRWENFWI4PGgSoDANFf8Uzbw43MGsC SkuNFR1DrFzdJHgQvOL684DxIMJl+EviFz/JnLXYEqDWxQpGzl7pF0OSX5H4GGnDYvqZ J9YGhdo8mrVV1uZWvnM/vf4nwBpnIwXx+Ttk4b8eT7nTUcRpVCvgk+HZQXzl536USxba ukYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=MmkG53WQLXsnChwuW4VZaCFghSpsaEReR7YJG6XS3wY=; b=tWhuc9wY7alzfH1iSUZ8BeLHuOthliFXRWhV0MSVwAwSyJn1t/XYfZzxtdZhrnSF41 7rkfAAIL8VzOd8y/xpknYkdkBU7uAXxjQpiap+9hl8b5/bAWY4V/PwylObeTblYg/pdT X9qBBK9M80cwG9rBJLVWJzpM0hAeGPri4baDTd+95pv04Aet2oeNWRx12xeNisOuh5UN CbEhLo3PwZFq3xCE6z9gigZ4pA4JgbRHpoYzHl7VOriLOPizO7BNvF7gBrSLntlp9OBD Hr1L7c+X89aCM9wDElSHjvSlpNsBvknSeH8xctcZqQzWUj2XtDB4H90RbDJM1859vG3g hlNg== X-Gm-Message-State: APjAAAW5Naf+dZhcc+3HGHAf8h7mOvtmHAy0eSGFB3h0rj/45gZYUdYS 5NdkDxCxLjT9eIMFUA6sDg0= X-Google-Smtp-Source: APXvYqyvGaG6S4s96AFzUFqGjV97xe/yb4IsOBocn5ACV+MMJMiG3jRLvG0CUcuacfGGqhXQuabsEg== X-Received: by 2002:a63:c106:: with SMTP id w6mr5390973pgf.422.1562862949567; Thu, 11 Jul 2019 09:35:49 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id w187sm6560127pfb.4.2019.07.11.09.35.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Jul 2019 09:35:49 -0700 (PDT) Date: Thu, 11 Jul 2019 09:35:48 -0700 From: Guenter Roeck To: Lei YU Cc: Jean Delvare , Eddie James , "Gustavo A . R . Silva" , linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hwmon (occ): Fix division by zero issue Message-ID: <20190711163548.GA19747@roeck-us.net> References: <1562813088-23708-1-git-send-email-mine260309@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1562813088-23708-1-git-send-email-mine260309@gmail.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 11, 2019 at 10:44:48AM +0800, Lei YU wrote: > The code in occ_get_powr_avg() invokes div64_u64() without checking the > divisor. In case the divisor is zero, kernel gets an "Division by zero > in kernel" error. > > Check the divisor and make it return 0 if the divisor is 0. > > Signed-off-by: Lei YU > Reviewed-by: Eddie James Applied. Thanks, Guenter > --- > drivers/hwmon/occ/common.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c > index 13a6290..f02aa40 100644 > --- a/drivers/hwmon/occ/common.c > +++ b/drivers/hwmon/occ/common.c > @@ -402,8 +402,10 @@ static ssize_t occ_show_power_1(struct device *dev, > > static u64 occ_get_powr_avg(u64 *accum, u32 *samples) > { > - return div64_u64(get_unaligned_be64(accum) * 1000000ULL, > - get_unaligned_be32(samples)); > + u64 divisor = get_unaligned_be32(samples); > + > + return (divisor == 0) ? 0 : > + div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor); > } > > static ssize_t occ_show_power_2(struct device *dev,