Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964977AbaGAVwf (ORCPT ); Tue, 1 Jul 2014 17:52:35 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:19959 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757136AbaGAVwR (ORCPT ); Tue, 1 Jul 2014 17:52:17 -0400 Message-ID: <53B32D80.8000601@oracle.com> Date: Tue, 01 Jul 2014 17:52:00 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Andrew Morton , Christoph Lameter CC: David Rientjes , Wei Yang , Pekka Enberg , Matt Mackall , "linux-mm@kvack.org" , LKML , Dave Jones Subject: Re: mm: slub: invalid memory access in setup_object References: <53AAFDF7.2010607@oracle.com> <20140701144947.5ce3f93729759d8f38d7813a@linux-foundation.org> In-Reply-To: <20140701144947.5ce3f93729759d8f38d7813a@linux-foundation.org> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/01/2014 05:49 PM, Andrew Morton wrote: > On Tue, 1 Jul 2014 09:58:52 -0500 (CDT) Christoph Lameter wrote: > >> On Mon, 30 Jun 2014, David Rientjes wrote: >> >>> It's not at all clear to me that that patch is correct. Wei? >> >> Looks ok to me. But I do not like the convoluted code in new_slab() which >> Wei's patch does not make easier to read. Makes it difficult for the >> reader to see whats going on. >> >> Lets drop the use of the variable named "last". >> >> >> Subject: slub: Only call setup_object once for each object >> >> Modify the logic for object initialization to be less convoluted >> and initialize an object only once. >> > > Well, um. Wei's changelog was much better: > > : When a kmem_cache is created with ctor, each object in the kmem_cache will > : be initialized before use. In the slub implementation, the first object > : will be initialized twice. > : > : This patch avoids the duplication of initialization of the first object. > : > : Fixes commit 7656c72b5a63: ("SLUB: add macros for scanning objects in a > : slab"). > > I can copy that text over and add the reported-by etc (ho hum) but I > have a tiny feeling that this patch hasn't been rigorously tested? > Perhaps someone (Wei?) can do that? > > And we still don't know why Sasha's kernel went oops. I only saw this oops once, and after David's message yesterday I tried reverting the patch he pointed out, but not much changed. Is there a better way to stress test slub? Thanks, Sasha -- 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/