From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752039AbeCMRsm (ORCPT ); Tue, 13 Mar 2018 13:48:42 -0400 Received: from vegas.theobroma-systems.com ([144.76.126.164]:51308 "EHLO mail.theobroma-systems.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932257AbeCMRsj (ORCPT ); Tue, 13 Mar 2018 13:48:39 -0400 Subject: Re: [PATCH v2 0/1] Open questions To: "Dr. Philipp Tomsich" Cc: Martin Elshuber , Wolfgang Grandegger , Marc Kleine-Budde , linux-can@vger.kernel.org, linux-kernel@vger.kernel.org References: <20180313173520.21257-1-jakob.unterwurzacher@theobroma-systems.com> <06378497-1ACE-4333-810F-4E3E4706CCD5@theobroma-systems.com> From: Jakob Unterwurzacher Message-ID: Date: Tue, 13 Mar 2018 18:48:36 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <06378497-1ACE-4333-810F-4E3E4706CCD5@theobroma-systems.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13.03.18 18:42, Dr. Philipp Tomsich wrote: > >> On 13 Mar 2018, at 18:40, Jakob Unterwurzacher wrote: >> >>>> + /* get the urb context */ >>>> + if (WARN_ON(!context)) >>>> + return; >>> >>> Can this happen? >> >> Not unless there is a bug in the code. But we want to get a message >> before dereferencing a pointer. > > Why not use BUG_ON(!context)? I believe BUG_ON kills the kernel - the intention was to get loud message, but we'd rather not crash the user's machine. Best regards, Jakob