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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 5E788C2BA83 for ; Sun, 9 Feb 2020 23:51:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3432620820 for ; Sun, 9 Feb 2020 23:51:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727798AbgBIXvs (ORCPT ); Sun, 9 Feb 2020 18:51:48 -0500 Received: from mga02.intel.com ([134.134.136.20]:53143 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726890AbgBIXvr (ORCPT ); Sun, 9 Feb 2020 18:51:47 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Feb 2020 15:51:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,423,1574150400"; d="scan'208";a="221382655" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga007.jf.intel.com with ESMTP; 09 Feb 2020 15:51:45 -0800 Date: Mon, 10 Feb 2020 07:52:02 +0800 From: Wei Yang To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, dan.j.williams@intel.com, richardw.yang@linux.intel.com, david@redhat.com Subject: Re: [PATCH 7/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Message-ID: <20200209235202.GC8705@richard> Reply-To: Wei Yang References: <20200209104826.3385-1-bhe@redhat.com> <20200209104826.3385-8-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200209104826.3385-8-bhe@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 09, 2020 at 06:48:26PM +0800, Baoquan He wrote: >In section_deactivate(), pfn_to_page() doesn't work any more after >ms->section_mem_map is resetting to NULL in SPARSEMEM|!VMEMMAP case. >It caused hot remove failure, the trace is: > >kernel BUG at mm/page_alloc.c:4806! >invalid opcode: 0000 [#1] SMP PTI >CPU: 3 PID: 8 Comm: kworker/u16:0 Tainted: G W 5.5.0-next-20200205+ #340 >Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 >Workqueue: kacpi_hotplug acpi_hotplug_work_fn >RIP: 0010:free_pages+0x85/0xa0 >Call Trace: > __remove_pages+0x99/0xc0 > arch_remove_memory+0x23/0x4d > try_remove_memory+0xc8/0x130 > ? walk_memory_blocks+0x72/0xa0 > __remove_memory+0xa/0x11 > acpi_memory_device_remove+0x72/0x100 > acpi_bus_trim+0x55/0x90 > acpi_device_hotplug+0x2eb/0x3d0 > acpi_hotplug_work_fn+0x1a/0x30 > process_one_work+0x1a7/0x370 > worker_thread+0x30/0x380 > ? flush_rcu_work+0x30/0x30 > kthread+0x112/0x130 > ? kthread_create_on_node+0x60/0x60 > ret_from_fork+0x35/0x40 > >Let's defer the ->section_mem_map resetting after depopulate_section_memmap() >to fix it. > >Signed-off-by: Baoquan He >--- > mm/sparse.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/mm/sparse.c b/mm/sparse.c >index 623755e88255..345d065ef6ce 100644 >--- a/mm/sparse.c >+++ b/mm/sparse.c >@@ -854,13 +854,15 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > ms->usage = NULL; > } > memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); >- ms->section_mem_map = (unsigned long)NULL; > } > > if (section_is_early && memmap) > free_map_bootmem(memmap); > else > depopulate_section_memmap(pfn, nr_pages, altmap); The crash happens in depopulate_section_memmap() when trying to get memmap by pfn_to_page(). Can we pass memmap directly? >+ >+ if(!rc) >+ ms->section_mem_map = (unsigned long)NULL; > } > > static struct page * __meminit section_activate(int nid, unsigned long pfn, >-- >2.17.2 -- Wei Yang Help you, Help me