From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f170.google.com (mail-ie0-f170.google.com [209.85.223.170]) by kanga.kvack.org (Postfix) with ESMTP id 2718D6B0031 for ; Tue, 1 Jul 2014 17:52:11 -0400 (EDT) Received: by mail-ie0-f170.google.com with SMTP id tr6so8784905ieb.15 for ; Tue, 01 Jul 2014 14:52:11 -0700 (PDT) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id bm3si36278709icb.49.2014.07.01.14.52.09 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 01 Jul 2014 14:52:10 -0700 (PDT) Message-ID: <53B32D80.8000601@oracle.com> Date: Tue, 01 Jul 2014 17:52:00 -0400 From: Sasha Levin MIME-Version: 1.0 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> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Christoph Lameter Cc: David Rientjes , Wei Yang , Pekka Enberg , Matt Mackall , "linux-mm@kvack.org" , LKML , Dave Jones 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org