From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162709AbdD0Oha (ORCPT ); Thu, 27 Apr 2017 10:37:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:40005 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753534AbdD0OhY (ORCPT ); Thu, 27 Apr 2017 10:37:24 -0400 Date: Thu, 27 Apr 2017 16:37:21 +0200 From: Michal Hocko To: Laurent Dufour Cc: Naoya Horiguchi , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org Subject: Re: [PATCH v2 1/2] mm: Uncharge poisoned pages Message-ID: <20170427143721.GK4706@dhcp22.suse.cz> References: <1493130472-22843-1-git-send-email-ldufour@linux.vnet.ibm.com> <1493130472-22843-2-git-send-email-ldufour@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1493130472-22843-2-git-send-email-ldufour@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 25-04-17 16:27:51, Laurent Dufour wrote: > When page are poisoned, they should be uncharged from the root memory > cgroup. > > This is required to avoid a BUG raised when the page is onlined back: > BUG: Bad page state in process mem-on-off-test pfn:7ae3b > page:f000000001eb8ec0 count:0 mapcount:0 mapping: (null) > index:0x1 > flags: 0x3ffff800200000(hwpoison) My knowledge of memory poisoning is very rudimentary but aren't those pages supposed to leak and never come back? In other words isn't the hoplug code broken because it should leave them alone? -- Michal Hocko SUSE Labs