Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754883Ab2JOVwn (ORCPT ); Mon, 15 Oct 2012 17:52:43 -0400 Received: from mail-la0-f46.google.com ([209.85.215.46]:63116 "EHLO mail-la0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403Ab2JOVwm (ORCPT ); Mon, 15 Oct 2012 17:52:42 -0400 Date: Tue, 16 Oct 2012 01:52:30 +0400 From: Cyrill Gorcunov To: Andrew Morton Cc: Stanislav Kinsbursky , viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, criu@openvz.org, ebiederm@xmission.com, rientjes@google.com, devel@openvz.org Subject: Re: [PATCH] proc: check vma->vm_file before dereferencing Message-ID: <20121015215230.GP19449@moon> References: <20121015152957.24859.7960.stgit@localhost.localdomain> <20121015144048.8fa16d28.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121015144048.8fa16d28.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1159 Lines: 33 On Mon, Oct 15, 2012 at 02:40:48PM -0700, Andrew Morton wrote: > On Mon, 15 Oct 2012 19:30:03 +0400 > Stanislav Kinsbursky wrote: > > > It can be equal to NULL. > > > > Please write better changelogs, so people do not have to ask questions > such as: > > - Under what conditions does this bug trigger? > > - In which kernel version(s)? > > - Is it a post-3.6 regression? Andrew, would the following changelog be enough? The commit 7b540d0646ce122f0ba4520412be91e530719742 switched proc_map_files_readdir to use @f_mode directly instead of grabbing @file reference, but same time the test for @vm_file presence was lost leading to nil dereference. The patch brings the test back. The all proc_map_files feature is CONFIG_CHECKPOINT_RESTORE wrapped (which is set to 'n' by default) so the bug doesn't affect regular kernels. The regression is 3.7-rc1 only as far as I can tell. -- 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/