Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932116Ab2BPCtM (ORCPT ); Wed, 15 Feb 2012 21:49:12 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:48235 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756449Ab2BPCtK (ORCPT ); Wed, 15 Feb 2012 21:49:10 -0500 Date: Wed, 15 Feb 2012 18:48:42 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Roland Dreier cc: Dave Jones , Andrew Morton , Andrea Arcangeli , David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fedoraproject.org Subject: Re: exit_mmap() BUG_ON triggering since 3.1 In-Reply-To: Message-ID: References: <20120215183317.GA26977@redhat.com> User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323584-1684060180-1329360529=:19722" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1770 Lines: 40 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323584-1684060180-1329360529=:19722 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE On Wed, 15 Feb 2012, Roland Dreier wrote: > On Wed, Feb 15, 2012 at 6:14 PM, Hugh Dickins wrote: > > My suspicion was that it would be related to Transparent HugePages: > > they do complicate the pagetable story. =A0And I think I have found a > > potential culprit. =A0I don't know if nr_ptes is the only loser from > > these two split_huge_pages calls, but assuming it is... >=20 > Do you have an idea when this bug might have been introduced? > Presumably it's been there since THP came in? That's right, since THP came in (2.6.38 on mainline, but IIRC Red Hat had THP applied to an earlier kernel). >=20 > The reason I ask is that I have one of these exit_mm BUG_ONs > in my pile of one-off unreproducible crashes, but in my case it > happened with 2.6.39 (with THP enabled). So I'm wondering if > I can cross it off my list and blame this bug, or if it remains one > of those inexplicable mysteries... If you think that system could have been using swap, yes, cross it off (unless someone points out that I'm totally wrong, because....). But if you know that system used no swap (and didn't get involved in any memory-failure hwpoison business), then keep on worrying! Hugh --8323584-1684060180-1329360529=:19722-- -- 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/