Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756799Ab3CHLiz (ORCPT ); Fri, 8 Mar 2013 06:38:55 -0500 Received: from mail-vb0-f42.google.com ([209.85.212.42]:56569 "EHLO mail-vb0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752522Ab3CHLix (ORCPT ); Fri, 8 Mar 2013 06:38:53 -0500 MIME-Version: 1.0 In-Reply-To: <87sj47t97s.fsf@xmission.com> References: <20130307132819.GA31162@localhost> <87sj47t97s.fsf@xmission.com> Date: Fri, 8 Mar 2013 17:38:52 +0600 Message-ID: Subject: Re: [nsproxy] BUG: unable to handle kernel NULL pointer dereference at 0000000000000024 From: Rakib Mullick To: "Eric W. Biederman" Cc: Fengguang Wu , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1116 Lines: 34 On 3/7/13, Eric W. Biederman wrote: > Fengguang Wu writes: > >> Greetings, >> >> I got the below oops and the first bad commit is > > Doh! On a second look that change is totally wrong. Of course we need > to up the ref-count every time we create a new process. Especially if > we don't do anything with namespaces. > > I was looking at it from the wrong angle last night. I should have > known better. > > Patch dropped. > Sad to know :( . From the debug messages, it's kmemcheck report. I can't related the problem specified with the patch I've proposed. It seems at task exit path, at switch_task_namespaces() - after my patch atomic_dec_and_test(&ns->count) becomes true (-1), thus free_nsproxy() gets called. But, free_nsproxy() shouldn't get called here. Am I right? Or there's something else? Thanks, Rakib -- 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/