Received: by 2002:a25:1985:0:0:0:0:0 with SMTP id 127csp2148332ybz; Sat, 2 May 2020 16:35:46 -0700 (PDT) X-Google-Smtp-Source: APiQypLsNaLuFMLZWRTgs9H1zzK3lW4JMcIJkVuAlvzEg8hVx2pEZerXs9elMoUrJ6tVgSvrvUAW X-Received: by 2002:a50:f288:: with SMTP id f8mr9145284edm.337.1588462545932; Sat, 02 May 2020 16:35:45 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1588462545; cv=none; d=google.com; s=arc-20160816; b=WNJhsTg1nlXuB8yZ3gJx+JzAvLTTwzp+gTQ8fX9yDHoDPiDzgAf0WHIiy9JUwxBJ4u VZw6Yso1rHGDH03UPh8oK8zfml2AE6RGiFPzqhrdsI1Ss6E98HejoYdAn8W/AbZ0hTdK YmX8qdUyUVNGbMjZaliGdF2pngWS5ryDqPNo8KYPfRguWepHAWU403M8OY92jLdZqf+S vVhjaLiPr1mLc9MSDlXs+ftPD9szMQiXc/F3C5W0qFf/a2e6SlkOMmfQWujnySn92smE xn+k0MgXSz6dDwEcVZMbOVb/VW39tuWoNInnHmwmJEL5vXXjNg/fFtZZYkmvE8bxihZT o5Xg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:from:subject:cc:to:message-id:date; bh=/1z1fdchEvzVgBfuw9ZDPqWyvA7iflekfmnL7qSgT1I=; b=Zu9sG4Ko4hbkFiDUU0GdYV2+oY9j8y+kHy8zrdCvrKdW4uLR0KONHtU3x5BbL0xD+x YaJ3YZv1ebL9CFjVrTrm5EezGoKP1spU6vYIsNL56LQ820Mq5rDFMjQkJVmpool1UHIX N4QPJEx4KK3Xa3lOcqsk0jtA/kz8NW+lo9WU60H0szZiT85Wv7v/95pfDG3X7R9Svtov s5K6Z77IA1tjbMR1nB6Y6rdoJGCbUA0StGKj/OHWI+j/G4Udetr/gOFyD7Wef7q7cOqh H12fWvBcjB1Oxi+4rUy/IYYvuSczeTqOZL3K3YTJG7lb6Qcz97TAogcS67zJg/14nS1/ nGFw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id y10si4265045ejw.403.2020.05.02.16.35.21; Sat, 02 May 2020 16:35:45 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726599AbgEBXdw (ORCPT + 99 others); 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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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.