From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB406C5CFEB for ; Wed, 11 Jul 2018 13:12:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A00B920846 for ; Wed, 11 Jul 2018 13:12:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A00B920846 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387640AbeGKNQr (ORCPT ); Wed, 11 Jul 2018 09:16:47 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37458 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726456AbeGKNQr (ORCPT ); Wed, 11 Jul 2018 09:16:47 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6030D80D2F6B; Wed, 11 Jul 2018 13:12:29 +0000 (UTC) Received: from localhost (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59851111AF17; Wed, 11 Jul 2018 13:12:28 +0000 (UTC) Date: Wed, 11 Jul 2018 21:12:25 +0800 From: Baoquan He To: Michael Ellerman Cc: akpm@linux-foundation.org, broonie@kernel.org, mhocko@suse.cz, sfr@canb.auug.org.au, linux-next@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mm-commits@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, pasha.tatashin@oracle.com, "Aneesh Kumar K.V" , Anshuman Khandual Subject: Re: Boot failures with "mm/sparse: Remove CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER" on powerpc (was Re: mmotm 2018-07-10-16-50 uploaded) Message-ID: <20180711131225.GI1969@MiWiFi-R3L-srv> References: <20180710235044.vjlRV%akpm@linux-foundation.org> <87lgai9bt5.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lgai9bt5.fsf@concordia.ellerman.id.au> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 11 Jul 2018 13:12:29 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Wed, 11 Jul 2018 13:12:29 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'bhe@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michael, On 07/11/18 at 10:49pm, Michael Ellerman wrote: > akpm@linux-foundation.org writes: > > The mm-of-the-moment snapshot 2018-07-10-16-50 has been uploaded to > > > > http://www.ozlabs.org/~akpm/mmotm/ > ... > > > * mm-sparse-add-a-static-variable-nr_present_sections.patch > > * mm-sparsemem-defer-the-ms-section_mem_map-clearing.patch > > * mm-sparsemem-defer-the-ms-section_mem_map-clearing-fix.patch > > * mm-sparse-add-a-new-parameter-data_unit_size-for-alloc_usemap_and_memmap.patch > > * mm-sparse-optimize-memmap-allocation-during-sparse_init.patch > > * mm-sparse-optimize-memmap-allocation-during-sparse_init-checkpatch-fixes.patch > > > * mm-sparse-remove-config_sparsemem_alloc_mem_map_together.patch > > This seems to be breaking my powerpc pseries qemu boots. > > The boot log with some extra debug shows eg: > > $ make pseries_le_defconfig > $ qemu-system-ppc64 -nographic -vga none -M pseries -m 2G -kernel vmlinux > vmemmap_populate f000000000000000..f000000000024000, node 0 > * f000000000000000..f000000001000000 allocated at c000000076000000 > hash__vmemmap_create_mapping: start 0xf000000000000000 size 0x1000000 phys 0x76000000 > hash__vmemmap_create_mapping: failed -1 > > > > Then there's lots of other warnings about bad page states and eventually > a NULL deref and we panic(). > > > The problem seems to be that we're calling down into > hash__vmemmap_create_mapping() for every call to vmemmap_populate(), > whereas previously we would only call hash__vmemmap_create_mapping() > once because our vmemmap_populated() would return true. > > There's actually a comment in sparse_init() that says: > > * powerpc need to call sparse_init_one_section right after each > * sparse_early_mem_map_alloc, so allocate usemap_map at first. > > So changing that behaviour does seem to be the problem. > > I assume that comment is talking about the fact that we use pfn_valid() > in vmemmap_populated(). > > I'm not clear on how to fix it though. Have you tried reverting that patch and building kernel to test again? Does it work?