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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 88044C47088 for ; Wed, 26 May 2021 08:07:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6635A613D8 for ; Wed, 26 May 2021 08:07:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232011AbhEZIIr (ORCPT ); Wed, 26 May 2021 04:08:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:36452 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229594AbhEZIIp (ORCPT ); Wed, 26 May 2021 04:08:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1622016433; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=qXmMuXVb6tV490lrV7VKGSnEUHok9pVADTgbbHbkGj0=; b=byko318foULpGG7GZ3OWDvHxPsWBem5g9+z9gGjWRMD+LptxjXyviyALYgvIV8V3Jn4jqK Mf9/WFdIgipjTioENvYUaENEIyaKjthC2lozWQiykTqjbzlp7OFg1ohnpv8CwMVO7e6hMO RlWRAvAcWyxWT6x7x04GrM2S+eppswI= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C683BAFA9; Wed, 26 May 2021 08:07:13 +0000 (UTC) Date: Wed, 26 May 2021 10:07:12 +0200 From: Michal Hocko To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Qian Cai , Andrew Morton , Anshuman Khandual , Oscar Salvador , Mike Rapoport Subject: Re: [PATCH v1] drivers/base/memory: fix trying offlining memory blocks with memory holes on aarch64 Message-ID: References: <20210526075226.5572-1-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526075226.5572-1-david@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 26-05-21 09:52:26, David Hildenbrand wrote: > offline_pages() properly checks for memory holes and bails out. However, > we do a page_zone(pfn_to_page(start_pfn)) before calling offline_pages() > when offlining a memory block. We should not unconditionally call > page_zone(pfn_to_page(start_pfn)) on aarch64 in offlining code, otherwise > we can trigger a BUG when hitting a memory hole: > > [ 162.327720][ T1694] kernel BUG at include/linux/mm.h:1383! > [ 162.333695][ T1694] Internal error: Oops - BUG: 0 [#1] SMP > [ 162.339181][ T1694] Modules linked in: loop processor efivarfs ip_tables x_tables ext4 mbcache jbd2 dm_mod igb nvme i2c_algo_bit mlx5_core i2c_core nvme_core firmware_class > [ 162.354604][ T1694] CPU: 13 PID: 1694 Comm: ranbug Not tainted 5.12.0-next-20210524+ #4 > [ 162.362601][ T1694] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020 > [ 162.371116][ T1694] pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--) > [ 162.377811][ T1694] pc : memory_subsys_offline+0x1f8/0x250 > [ 162.383295][ T1694] lr : memory_subsys_offline+0x1f8/0x250 > [ 162.388773][ T1694] sp : ffff80002458f8e0 > [ 162.392773][ T1694] x29: ffff80002458f8e0 x28: ffff800010914d30 x27: 0000000000000000 > [ 162.400602][ T1694] x26: 0000000000002000 x25: 1fffe00002550401 x24: ffff000012a82008 > [ 162.408431][ T1694] x23: fffffc0000000000 x22: 0000000000008000 x21: 0000000000000001 > [ 162.416259][ T1694] x20: ffffffffffffffff x19: ffff000012a82018 x18: ffff0008527b6a70 > [ 162.424086][ T1694] x17: 0000000000000000 x16: 0000000000000007 x15: 00000000000000c8 > [ 162.431914][ T1694] x14: 0000000000000000 x13: ffff800011c6eea4 x12: ffff60136ceb8574 > [ 162.439742][ T1694] x11: 1fffe0136ceb8573 x10: ffff60136ceb8573 x9 : dfff800000000000 > [ 162.447570][ T1694] x8 : ffff009b675c2b9b x7 : 0000000000000001 x6 : ffff009b675c2b98 > [ 162.455398][ T1694] x5 : 00009fec93147a8d x4 : ffff009b675c2b98 x3 : 1fffe0010a4f6c09 > [ 162.463226][ T1694] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000034 > [ 162.471054][ T1694] Call trace: > [ 162.474186][ T1694] memory_subsys_offline+0x1f8/0x250 > [ 162.479318][ T1694] device_offline+0x154/0x1d8 > [ 162.483844][ T1694] online_store+0xa4/0x118 > [ 162.488107][ T1694] dev_attr_store+0x44/0x78 > [ 162.492457][ T1694] sysfs_kf_write+0xe8/0x138 > [ 162.496896][ T1694] kernfs_fop_write_iter+0x26c/0x3d0 > [ 162.502028][ T1694] new_sync_write+0x2bc/0x4f8 > [ 162.506552][ T1694] vfs_write+0x718/0xc88 > [ 162.510643][ T1694] ksys_write+0xf8/0x1e0 > [ 162.514732][ T1694] __arm64_sys_write+0x74/0xa8 > [ 162.519342][ T1694] invoke_syscall.constprop.0+0x78/0x1e8 > [ 162.524824][ T1694] do_el0_svc+0xe4/0x298 > [ 162.528914][ T1694] el0_svc+0x20/0x30 > [ 162.532658][ T1694] el0_sync_handler+0xb0/0xb8 > [ 162.537181][ T1694] el0_sync+0x178/0x180 > [ 162.541187][ T1694] Code: f00033e1 91318021 91090021 97e38d8b (d4210000) > [ 162.547968][ T1694] ---[ end trace 2a1964462a219f20 ]--- > [ 162.553273][ T1694] Kernel panic - not syncing: Oops - BUG: Fatal exception > [ 162.560250][ T1694] SMP: stopping secondary CPUs > [ 162.564871][ T1694] Kernel Offset: disabled > [ 162.569045][ T1694] CPU features: 0x00000251,20000846 > [ 162.574089][ T1694] Memory Limit: none > [ 162.577849][ T1694] ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]--- > > If nr_vmemmap_pages is set, we know that we are dealing with hotplugged > memory that doesn't have any holes. So call > page_zone(pfn_to_page(start_pfn)) only when really necessary -- when > nr_vmemmap_pages is set and we actually adjust the present pages. > > Fixes: a08a2ae34613 ("mm,memory_hotplug: allocate memmap from the added memory range") > Reported-by: Qian Cai (QUIC) > Cc: Andrew Morton > Cc: Anshuman Khandual > Cc: Michal Hocko > Cc: Oscar Salvador > Cc: Mike Rapoport > Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Thanks! > --- > drivers/base/memory.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index b31b3af5c490..d5ffaab3cb61 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -218,14 +218,14 @@ static int memory_block_offline(struct memory_block *mem) > struct zone *zone; > int ret; > > - zone = page_zone(pfn_to_page(start_pfn)); > - > /* > * Unaccount before offlining, such that unpopulated zone and kthreads > * can properly be torn down in offline_pages(). > */ > - if (nr_vmemmap_pages) > + if (nr_vmemmap_pages) { > + zone = page_zone(pfn_to_page(start_pfn)); > adjust_present_page_count(zone, -nr_vmemmap_pages); > + } > > ret = offline_pages(start_pfn + nr_vmemmap_pages, > nr_pages - nr_vmemmap_pages); > -- > 2.31.1 -- Michal Hocko SUSE Labs