Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755485Ab3E3NVP (ORCPT ); Thu, 30 May 2013 09:21:15 -0400 Received: from mail-la0-f52.google.com ([209.85.215.52]:64650 "EHLO mail-la0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755230Ab3E3NVE (ORCPT ); Thu, 30 May 2013 09:21:04 -0400 MIME-Version: 1.0 In-Reply-To: References: <1369817109-4277-1-git-send-email-benjamin.tissoires@redhat.com> Date: Thu, 30 May 2013 15:21:02 +0200 Message-ID: Subject: Re: [PATCH] HID: multitouch: prevent memleak with the allocated name From: Benjamin Tissoires To: Andy Shevchenko Cc: Benjamin Tissoires , Henrik Rydberg , Jiri Kosina , Stephane Chatty , linux-input , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1617 Lines: 44 Hi Andy, On Wed, May 29, 2013 at 10:12 PM, Andy Shevchenko wrote: > On Wed, May 29, 2013 at 11:45 AM, Benjamin Tissoires > wrote: >> mt_free_input_name() was never called during .remove(): >> hid_hw_stop() removes the hid_input items in hdev->inputs, and so the >> list is therefore empty after the call. In the end, we never free the >> special names that has been allocated during .probe(). >> >> Restore the original name before freeing it to avoid acessing already >> freed pointer. >> > >> I just spotted this one yesterday... My guess is that this way is safe (without >> a locking mechanism to prevent accessing hi->input->name), but I'm not 100% sure. > > Hi Jiri, Benjamin. > > What do you think about patch I just sent? Thanks for looking at this. My very first concern is that none of the HID part has been devm-ized (this is on my todo-if-I-have-some-time list). The input susbsystem has been devm-ized quite recently, so this should be possible now. So, basically, I honestly don't know if using part of devm mallocs in hid-multitouch is safe and if it will work as expected. Maybe Jiri will have a better idea. I have a few comments on your patch if Jiri wants to include it. > > P.S. Benjamin, I re-used your commit message, I think you have no objections. No objections :) Cheers, Benjamin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/