From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759797AbbFBR5x (ORCPT ); Tue, 2 Jun 2015 13:57:53 -0400 Received: from mail-la0-f51.google.com ([209.85.215.51]:33780 "EHLO mail-la0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759432AbbFBR5p (ORCPT ); Tue, 2 Jun 2015 13:57:45 -0400 Message-ID: <556DEE94.3030203@cogentembedded.com> Date: Tue, 02 Jun 2015 20:57:40 +0300 From: Sergei Shtylyov Organization: Cogent Embedded User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Laurent Pinchart CC: Colin King , Greg Kroah-Hartman , Felipe Balbi , Sudeep Holla , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][V2] usb: isp1760: fix null dereference if kzalloc returns null References: <1433112223-4651-1-git-send-email-colin.king@canonical.com> <556C6362.1010700@cogentembedded.com> <2412438.ObMLH8QmsQ@avalon> In-Reply-To: <2412438.ObMLH8QmsQ@avalon> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 06/02/2015 06:41 PM, Laurent Pinchart wrote: >>> From: Colin Ian King >>> If kzalloc returns null then isp1760_ep_alloc_request performs >>> a null pointer dereference on req. Check for null to avoid this. >> I told you there's no dereference and yet you're repeating it again. :-( > How about > "isp1760_ep_alloc_request allocates a structure with kzalloc without checking > for NULL and then returns a pointer to one of the structure fields. As the > field happens to be the first in the structure the caller can properly check > for NULL, but this is risky if the structure layout is changed later. Add an > explicit NULL check for the kzalloc return value." Fine with me! Thanks, Laurent. :-) >>> a null pointer dereference on req. Check for null to avoid this. >>> Detected with smatch static analysis: >>> drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request() >>> error: potential null dereference 'req'. (kzalloc returns null) >>> Signed-off-by: Colin Ian King WBR, Sergei