From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751927AbdFZOto (ORCPT ); Mon, 26 Jun 2017 10:49:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51456 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751366AbdFZOti (ORCPT ); Mon, 26 Jun 2017 10:49:38 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 295C281243 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jglisse@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 295C281243 Date: Mon, 26 Jun 2017 10:49:34 -0400 From: Jerome Glisse To: Ingo Molnar Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Logan Gunthorpe , Andrew Morton Subject: Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v3 Message-ID: <20170626144934.GA3706@redhat.com> References: <20170624180514.3821-1-jglisse@redhat.com> <20170626094304.bmvsia5zpixbazpu@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170626094304.bmvsia5zpixbazpu@gmail.com> User-Agent: Mutt/1.8.2 (2017-04-18) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 26 Jun 2017 14:49:37 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 26, 2017 at 11:43:04AM +0200, Ingo Molnar wrote: > > * jglisse@redhat.com wrote: > > > From: Jérôme Glisse > > > > With commit af2cf278ef4f we no longer free pud so that we do not > > have synchronize all pgd on hotremove/vfree. But the new 5 level > > page table patchset reverted that for 4 level page table. > > > > This patch restore af2cf278ef4f and disable free_pud() if we are > > in the 4 level page table case thus avoiding BUG_ON() after hot- > > remove. > > > > af2cf278ef4f x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() > > Am I correct that the _real_ buggy commit that introduced the breakage in v4.12 > is: > > f2a6a7050109: ("x86: Convert the rest of the code to support p4d_t") > > ... right? Correct. Jérôme