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[209.132.180.67]) by mx.google.com with ESMTP id i78si11172843oib.1.2020.02.19.22.13.03; Wed, 19 Feb 2020 22:13:16 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726494AbgBTGLy (ORCPT + 99 others); Thu, 20 Feb 2020 01:11:54 -0500 Received: from mga12.intel.com ([192.55.52.136]:62141 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725942AbgBTGLy (ORCPT ); Thu, 20 Feb 2020 01:11:54 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Feb 2020 22:11:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,463,1574150400"; d="scan'208";a="434727879" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga005.fm.intel.com with ESMTP; 19 Feb 2020 22:11:51 -0800 Date: Thu, 20 Feb 2020 14:11:51 +0800 From: Wei Yang To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, richardw.yang@linux.intel.com, david@redhat.com, osalvador@suse.de, dan.j.williams@intel.com, mhocko@suse.com, rppt@linux.ibm.com, robin.murphy@arm.com Subject: Re: [PATCH v2 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Message-ID: <20200220061151.GA32521@richard> Reply-To: Wei Yang References: <20200220043316.19668-1-bhe@redhat.com> <20200220043316.19668-2-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220043316.19668-2-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 Thu, Feb 20, 2020 at 12:33:10PM +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: > >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 move the ->section_mem_map resetting after depopulate_section_memmap() >to fix it. > >Signed-off-by: Baoquan He Reviewed-by: Wei Yang >--- > mm/sparse.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/mm/sparse.c b/mm/sparse.c >index 596b2a45b100..b8e52c8fed7f 100644 >--- a/mm/sparse.c >+++ b/mm/sparse.c >@@ -779,13 +779,15 @@ 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); >+ >+ if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) >+ 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