From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751477AbdFZJnJ (ORCPT ); Mon, 26 Jun 2017 05:43:09 -0400 Received: from mail-wr0-f194.google.com ([209.85.128.194]:36186 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751353AbdFZJnI (ORCPT ); Mon, 26 Jun 2017 05:43:08 -0400 Date: Mon, 26 Jun 2017 11:43:04 +0200 From: Ingo Molnar To: jglisse@redhat.com 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: <20170626094304.bmvsia5zpixbazpu@gmail.com> References: <20170624180514.3821-1-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170624180514.3821-1-jglisse@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * 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? Thanks, Ingo