From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx108.postini.com [74.125.245.108]) by kanga.kvack.org (Postfix) with SMTP id C69BB6B005C for ; Mon, 11 Jun 2012 14:31:56 -0400 (EDT) Received: by mail-vc0-f182.google.com with SMTP id fy7so2542262vcb.41 for ; Mon, 11 Jun 2012 11:31:56 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20120608141945.4df63d95.akpm@linux-foundation.org> References: <1338405610-1788-1-git-send-email-pshelar@nicira.com> <20120608131045.90708bda.akpm@linux-foundation.org> <20120608141945.4df63d95.akpm@linux-foundation.org> Date: Mon, 11 Jun 2012 11:31:55 -0700 Message-ID: Subject: Re: [Resend PATCH v2] mm: Fix slab->page _count corruption. From: Pravin Shelar Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Christoph Lameter , penberg@kernel.org, aarcange@redhat.com, linux-mm@kvack.org, abhide@nicira.com, Jesse Gross On Fri, Jun 8, 2012 at 2:19 PM, Andrew Morton w= rote: > On Fri, 8 Jun 2012 13:23:56 -0700 > Pravin Shelar wrote: > >> On Fri, Jun 8, 2012 at 1:15 PM, Christoph Lameter wrote: >> > On Fri, 8 Jun 2012, Andrew Morton wrote: >> > >> >> OK. __I assume this bug has been there for quite some time. >> > >> > Well the huge pages refcount tricks caused the issue. >> > >> >> How serious is it? __Have people been reporting it in real workloads? >> >> How to trigger it? __IOW, does this need -stable backporting? >> > >> > Possibly. >> >> If this patch is getting back-ported then we shld also do same for >> 5bf5f03c271907978 (mm: fix slab->page flags corruption) which fixes >> other issue related to slub =A0and huge page sharing. > > Well I don't know if either are getting backported yet. > > To decide that we would have to understand the end-user impact of the > bug(s). =A0Please tell us? > We are working on zero copy io over skb in Open-vswitch. thats when we so this panic when we tried to get_page() over skb linear data allocated slub. But then I realized that it could potentially affect other subsystems as well, e.g. xfs and ocfs, which does page struct updates on slub objects. -- 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