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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 B4124C10F26 for ; Sat, 7 Mar 2020 20:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A9F32075A for ; Sat, 7 Mar 2020 20:59:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583614774; bh=5d3Oip03/coW7PPRWqkmaJXd6+0g1van/+FSAiBvGgU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=lgKVgW2WZ30h9CqXSBk66fzlTu+O3SgEaJdAXfIulWbLhYjZQF/D9yjeJ7bennJyA /ZZyG4KvXEPCTGV3Mbbgjw09X55nHQVxBmp2/3U+nLLk4J1rKogP6v+3o9NP9G1+Lf kBO8N0fsvAB+jqhr440sr9Jzu71k9GhFrJVHqM4Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726289AbgCGU7c (ORCPT ); Sat, 7 Mar 2020 15:59:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:53556 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726098AbgCGU7c (ORCPT ); Sat, 7 Mar 2020 15:59:32 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E4EB520684; Sat, 7 Mar 2020 20:59:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583614772; bh=5d3Oip03/coW7PPRWqkmaJXd6+0g1van/+FSAiBvGgU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Jwr3HrLwzhKeT1MNi4405W6ajHbQO1VkY6Hk8xqcmkAHCUUTMLmGUOO9cBD/9VcaP T5GSMRBEwfhRT37kVexan1Hr03ly009hYQpDC+tclYYfTPuMhnv7GVTY4SnyBO18Nr MJhvsJh5fS8BxPbbutzrFtaF76hYYfcE5457ZAag= Date: Sat, 7 Mar 2020 12:59:31 -0800 From: Andrew Morton To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, david@redhat.com, richardw.yang@linux.intel.com, dan.j.williams@intel.com, osalvador@suse.de, rppt@linux.ibm.com Subject: Re: [PATCH v3 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Message-Id: <20200307125931.8e75709181f5c4bda40b1ee5@linux-foundation.org> In-Reply-To: <20200307084229.28251-2-bhe@redhat.com> References: <20200307084229.28251-1-bhe@redhat.com> <20200307084229.28251-2-bhe@redhat.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 7 Mar 2020 16:42:23 +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. Thanks. I think I'll cherrypick this fix and shall await more review/testing input on the rest of the series.