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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 7C363C4BA18 for ; Wed, 26 Feb 2020 18:09:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3F21D24670 for ; Wed, 26 Feb 2020 18:09:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="kyRX5Cn0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F21D24670 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E59A86B000A; Wed, 26 Feb 2020 13:09:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E0A346B000C; Wed, 26 Feb 2020 13:09:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D47D06B0072; Wed, 26 Feb 2020 13:09:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0062.hostedemail.com [216.40.44.62]) by kanga.kvack.org (Postfix) with ESMTP id BD3676B000A for ; Wed, 26 Feb 2020 13:09:27 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 84D121F1D for ; Wed, 26 Feb 2020 18:09:27 +0000 (UTC) X-FDA: 76533065574.20.horn00_5284aa68c5548 X-HE-Tag: horn00_5284aa68c5548 X-Filterd-Recvd-Size: 5075 Received: from mail-ot1-f65.google.com (mail-ot1-f65.google.com [209.85.210.65]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Wed, 26 Feb 2020 18:09:26 +0000 (UTC) Received: by mail-ot1-f65.google.com with SMTP id g96so257320otb.13 for ; Wed, 26 Feb 2020 10:09:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=e/1VSrHV/eL0yjS7JzLq6CkDS40xQ5EKyFULmMfEARM=; b=kyRX5Cn0P/ON9gnA/ScfZ7oJkXAhWPXVLNx+beL35VdYa4shGdzN7u2FcFsUM++b2n lhoSm+twMkJopIMCGGM6P0DGpCliQXivQ8UpJyka/vhLBPkgOCPJDP/s+V9fbFyvQJE4 xo6pmVrTBkETwSWsQy8QMmWmUnhGOxr9bgYfeRj/XsqigRK7XQJDhsIPziELekou41N9 iN+TTGLkjTU4S70vyvb2VpcHy6jjx9Ds4AIgYEFIvD1CR50wVHkNf6Y2mEJ4MK+nNgCT RdvdyuO737GSlyOH6abS0gvyNKu+23jdoYyLCrOrolzytxlbMhwTO1Sy6CanmAKvf9UB Zcog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=e/1VSrHV/eL0yjS7JzLq6CkDS40xQ5EKyFULmMfEARM=; b=SPjY1uD27qNmiezbfH2FEN4K4TDDZSi4N3XZFIrBQul35wDbjdribQayyATQ7CXOgo fmuMR8Frk9C8FqHzK7+CuEzLFvPWnuOxTi/OeGS7/HSOZ9YxPIJSViuZcAHIGmxLJyty 5USLANbEMFMt545Jjzq3eQUPX82oT0uJOW7bK3xy8mtOohkDPBTurOSqwnC+K71zr3h4 FRugnpwgILH8PeXs7pKiJ7JewgPF2MfEmKeC28xgiAGYES/5dRjUPfT3pkVV++GNaRNO sekC8Wp2KafOzafj0cBOXnExWYFMak3h2CIBHua169vu89nt9X4OXLWVPUCoIAiogSNV NCAw== X-Gm-Message-State: APjAAAXgHJ7279mCq4woFczx4lQUi5hqPlOCmU2q3wrkWPFsgwKbeh0B rD0TuMdHIpH63Ubgdh+tsMTdDt2Rpk1Te6ACPVZEQQ== X-Google-Smtp-Source: APXvYqxexJYWBUQ0767VigneOX3hNatJ8i0pFmq0VMgMtXbecSlgtD1dW4b8q+DHv6aKK0BddyFnlOYVd5ZbJwfV+KY= X-Received: by 2002:a9d:7852:: with SMTP id c18mr3941574otm.247.1582740565960; Wed, 26 Feb 2020 10:09:25 -0800 (PST) MIME-Version: 1.0 References: <20200220043316.19668-1-bhe@redhat.com> <20200220043316.19668-2-bhe@redhat.com> In-Reply-To: <20200220043316.19668-2-bhe@redhat.com> From: Dan Williams Date: Wed, 26 Feb 2020 10:09:15 -0800 Message-ID: Subject: Re: [PATCH v2 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case To: Baoquan He Cc: Linux Kernel Mailing List , Linux MM , Andrew Morton , Wei Yang , David Hildenbrand , Oscar Salvador , Michal Hocko , Mike Rapoport , Robin Murphy Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Feb 19, 2020 at 8:34 PM 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 > --- > 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; Looks good to me: Reviewed-by: Dan Williams