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=-3.8 required=3.0 tests=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 C8136C47247 for ; Sat, 2 May 2020 23:33:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B165620757 for ; Sat, 2 May 2020 23:33:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726598AbgEBXdw (ORCPT ); Sat, 2 May 2020 19:33:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726375AbgEBXdw (ORCPT ); Sat, 2 May 2020 19:33:52 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BFBDC061A0C; Sat, 2 May 2020 16:33:52 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 5C6451515F5D8; Sat, 2 May 2020 16:33:51 -0700 (PDT) Date: Sat, 02 May 2020 16:33:50 -0700 (PDT) Message-Id: <20200502.163350.2198213381488533981.davem@davemloft.net> To: mmrmaximuzz@gmail.com Cc: peppe.cavallaro@st.com, alexandre.torgue@st.com, joabreu@synopsys.com, mcoquelin.stm32@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] stmmac: fix pointer check after utilization in stmmac_interrupt From: David Miller In-Reply-To: <20200502092906.GA9883@maxim-hplinux> References: <20200502092906.GA9883@maxim-hplinux> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 02 May 2020 16:33:51 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Maxim Petrov Date: Sat, 2 May 2020 12:29:08 +0300 > The paranoidal pointer check in IRQ handler looks very strange - it > really protects us only against bogus drivers which request IRQ line > with null pointer dev_id. However, the code fragment is incorrect > because the dev pointer is used before the actual check. That leads > to undefined behavior thus compilers are free to remove the pointer > check at all. > > Signed-off-by: Maxim Petrov Seriously, just remove this check altogether.