From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759905Ab2CGTem (ORCPT ); Wed, 7 Mar 2012 14:34:42 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:41331 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753540Ab2CGTej (ORCPT ); Wed, 7 Mar 2012 14:34:39 -0500 Date: Wed, 7 Mar 2012 23:34:33 +0400 From: Cyrill Gorcunov To: Oleg Nesterov Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, adobriyan@gmail.com, ebiederm@xmission.com, keescook@chromium.org, kosaki.motohiro@jp.fujitsu.com, matthltc@us.ibm.com, tj@kernel.org, xemul@parallels.com Subject: Re: + mm-exec-rename-mm-exe_file-to-mm-exe_path.patch added to -mm tree Message-ID: <20120307193433.GP20619@moon> References: <20120306231325.D4B26A0395@akpm.mtv.corp.google.com> <20120307162630.GG20558@moon> <20120307174113.GA25366@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120307174113.GA25366@redhat.com> 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 On Wed, Mar 07, 2012 at 06:41:13PM +0100, Oleg Nesterov wrote: ... > > Of course I can be wrong, but currently I think that either this patch > reveals another problem (unlikley), or (most likely) I did some stupid > mistake. > > Can you send me the reproducer just in case? > > > [ 1961.066410] Code: 41 5c 41 5d c9 c3 55 48 89 e5 41 54 53 48 83 ec 30 > > 66 66 66 66 90 48 63 c2 89 55 cc 48 89 fb 48 8d 04 06 48 89 45 e8 48 8b > > 7f 08 <48> 8b 87 a8 00 00 00 48 85 c0 74 0d 48 8b 40 38 48 85 c0 74 04 > > No sure I understand this asm... Looks like path->dentry is NULL, strange. > > I do not think I really need it, but just in case... could you send me > (privately) the result of "make fs/dcache.s" ? > yes, just sent. > I'll try to recheck the patch and think. > > But if you can _explain_ why do you think that "struct path" can't work, > please explain ;) OK, the best way to prove myself that I was wrong is to try to explain why it can't work. So I prepared a call trace to point where we can get a reference to non-existing path and... found that it's simply impossible. So then I tried to repeat oops after the test machine got rebooted and found that I can't repeat it. I'll continue testing but I think it was unrelated OOPs. Sorry for false alarm, Oleg! Cyrill