From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 1C9AC6B29C7 for ; Thu, 23 Aug 2018 07:16:36 -0400 (EDT) Received: by mail-qt0-f197.google.com with SMTP id y46-v6so4364943qth.9 for ; Thu, 23 Aug 2018 04:16:36 -0700 (PDT) Received: from mx1.redhat.com (mx3-rdu2.redhat.com. [66.187.233.73]) by mx.google.com with ESMTPS id k16-v6si955176qvc.79.2018.08.23.04.16.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Aug 2018 04:16:35 -0700 (PDT) Date: Thu, 23 Aug 2018 07:16:34 -0400 (EDT) From: Mikulas Patocka Subject: Re: A crash on ARM64 in move_freepages_block due to uninitialized pages in reserved memory In-Reply-To: <20180823111024.GC29735@dhcp22.suse.cz> Message-ID: References: <20180821104418.GA16611@dhcp22.suse.cz> <20180823111024.GC29735@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: James Morse , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, Pavel Tatashin On Thu, 23 Aug 2018, Michal Hocko wrote: > On Thu 23-08-18 07:02:37, Mikulas Patocka wrote: > [...] > > This crash is not from -ENOENT. It crashes because page->compound_head is > > 0xffffffffffffffff (see below). > > > > If I enable CONFIG_DEBUG_VM, I also get VM_BUG. > > This smells like the struct page is not initialized properly. How is > this memory range added? I mean is it brought up by the memory hotplug > or during the boot? > -- > Michal Hocko > SUSE Labs During the boot. There's not hotplug. Mikulas