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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41820C54EE9 for ; Wed, 7 Sep 2022 20:57:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CF9256B0072; Wed, 7 Sep 2022 16:57:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA9026B0073; Wed, 7 Sep 2022 16:57:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B71566B0074; Wed, 7 Sep 2022 16:57:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id AA5256B0072 for ; Wed, 7 Sep 2022 16:57:49 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 7887C160C6A for ; Wed, 7 Sep 2022 20:57:49 +0000 (UTC) X-FDA: 79886501058.26.EE9F26D Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf13.hostedemail.com (Postfix) with ESMTP id C224D20078 for ; Wed, 7 Sep 2022 20:57:48 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 82CE7B81E8D; Wed, 7 Sep 2022 20:57:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA21FC433D7; Wed, 7 Sep 2022 20:57:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1662584266; bh=M3X1Fu8uJkdINUMZjOBKC9XseWp6XKA8vDZ8k1t7Psk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fc4X9+IFTF1HvAdXY57/coSz56GR3yIRiAlKXdt1EuyR1k9/rHPKJufpkdOs8XNc0 2RmlzrcO72hQUEQQkiDMXXawDRXf+0+ac2BgLJUG7viD875RorrUgo1NxAnKsDh7/d Eu8C5oD2Rgop0YrRU04vqqGzd2r28/w65FKdHj+s= Date: Wed, 7 Sep 2022 13:57:45 -0700 From: Andrew Morton To: Naoya Horiguchi Cc: David Hildenbrand , linux-mm@kvack.org, Muchun Song , Miaohe Lin , Matthew Wilcox , Michal Hocko , Yang Shi , Naoya Horiguchi Subject: Re: [PATCH] mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all() Message-Id: <20220907135745.cda0d84b5a3f9f6df39b9884@linux-foundation.org> In-Reply-To: <20220907121157.GA2954283@ik1-406-35019.vs.sakura.ne.jp> References: <20220907100855.GA2894785@ik1-406-35019.vs.sakura.ne.jp> <1481ce19-0a64-d1dc-4d89-4db71d6f7eb3@redhat.com> <20220907121157.GA2954283@ik1-406-35019.vs.sakura.ne.jp> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=fc4X9+IF; spf=pass (imf13.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662584268; a=rsa-sha256; cv=none; b=WlA46HpRFw5BgZd7ZO4YKlne4vKeVcVIJFBO9tt224UetBr3NxXiWRT2jOdLXgVUsIR4oH 5yWk1D+ZXr7q54k8FXVQ4hCgdPioupEeFU8fxqDiX5JqYOLiHn1xVCvFmGAS6DD3ggJIwI qOos4RxVNoKhHVtj4Fth1QnL/t+v50A= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662584268; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=g1NQeYvbww0BAr3EFsUeUfHlQX5roazhvo0Navf5MQ0=; b=mpzf9Wp2Q4s/pkXfQelBpEDLTlyuBadgNoJ4FElRk1747GJQmm92jxTlaEHv7fizehZnZ1 aLd8aAYTAGTLvVRAFqqL+E0KRIGH2IvVhH614wJ8UYJwv1U6nvn6aeC9imh4Z/d2tUl7i1 +x8teej241oiCPEYL/mCadeebeWJswM= X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: C224D20078 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=fc4X9+IF; spf=pass (imf13.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspam-User: X-Stat-Signature: xzauytpi6sf4bazc641fpqwykho8aqjq X-HE-Tag: 1662584268-198728 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, 7 Sep 2022 21:11:57 +0900 Naoya Horiguchi wrote: > > NULL pointer dereference is triggered when calling thp split via debugfs > on the system with offlined memory blocks. With debug option enabled, > the following kernel messages are printed out: > > page:00000000467f4890 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121c000 > flags: 0x17fffc00000000(node=0|zone=2|lastcpupid=0x1ffff) > raw: 0017fffc00000000 0000000000000000 dead000000000122 0000000000000000 > raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 > page dumped because: unmovable page > page:000000007d7ab72e is uninitialized and poisoned > page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) > ------------[ cut here ]------------ > kernel BUG at include/linux/mm.h:1248! > invalid opcode: 0000 [#1] PREEMPT SMP PTI > CPU: 16 PID: 20964 Comm: bash Tainted: G I 6.0.0-rc3-foll-numa+ #41 > ... > RIP: 0010:split_huge_pages_write+0xcf4/0xe30 > > This shows that page_to_nid() in page_zone() is unexpectedly called for an > offlined memmap. > > Use pfn_to_online_page() to get struct page in PFN walker. > > Fixes: 49071d436b51 ("thp: add debugfs handle to split all huge pages") January of 2016! Or was this a long-term bug which was recently exposed by some other change?