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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 AACE8C10F00 for ; Sat, 7 Mar 2020 08:43:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D4FC20675 for ; Sat, 7 Mar 2020 08:43:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OTdyJeZx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726296AbgCGImq (ORCPT ); Sat, 7 Mar 2020 03:42:46 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:57663 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726193AbgCGImp (ORCPT ); Sat, 7 Mar 2020 03:42:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583570564; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=UraJ83HV2pn1X1NXn9FVFonewL2jW9cZzbayED9iRfE=; b=OTdyJeZxd2W3qGlS0iDvlJWyvyEGREpDoWgq503bd1bnW9ekcAJje/sm03rcMqNPtnefxn 3p7C5bNoQErTx6KqFSM/JO/dIxvfK/L79INxWDMMT/gVoWZVw16auIK2fVPrw9gH3Rrjc7 lwytW+E/x5O2V75a94vRpXDWIJ/6Tk8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-223-lQgXJX1vNaCwwzLzbAGmqw-1; Sat, 07 Mar 2020 03:42:42 -0500 X-MC-Unique: lQgXJX1vNaCwwzLzbAGmqw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4D88B13EA; Sat, 7 Mar 2020 08:42:41 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-29.pek2.redhat.com [10.72.12.29]) by smtp.corp.redhat.com (Postfix) with ESMTP id 143B95D9CA; Sat, 7 Mar 2020 08:42:37 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com, david@redhat.com, richardw.yang@linux.intel.com, dan.j.williams@intel.com, osalvador@suse.de, rppt@linux.ibm.com, bhe@redhat.com Subject: [PATCH v3 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Date: Sat, 7 Mar 2020 16:42:23 +0800 Message-Id: <20200307084229.28251-2-bhe@redhat.com> In-Reply-To: <20200307084229.28251-1-bhe@redhat.com> References: <20200307084229.28251-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") Signed-off-by: Baoquan He Cc: stable@vger.kernel.org --- mm/sparse.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/sparse.c b/mm/sparse.c index 42c18a38ffaa..1b50c15677d7 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -734,6 +734,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, struct mem_section *ms = __pfn_to_section(pfn); bool section_is_early = early_section(ms); struct page *memmap = NULL; + bool empty = false; unsigned long *subsection_map = ms->usage ? &ms->usage->subsection_map[0] : NULL; @@ -764,7 +765,8 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified */ bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); - if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) { + empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION); + if (empty) { unsigned long section_nr = pfn_to_section_nr(pfn); /* @@ -779,13 +781,15 @@ 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 (empty) + ms->section_mem_map = (unsigned long)NULL; } static struct page * __meminit section_activate(int nid, unsigned long pfn, -- 2.17.2