From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3463848-1520955562-2-12176588699165213963 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520955561; b=AQDgyw36lfPLVi4jFofhMJP06AgHvIeeiDdmvcGNm2h34g8 nSa3rK4zG4hsBBQ/hGnP+man/e352rd5Qfl1uYQGQ7vRCr9ebwjdhZPIH1HOZNiO sfyin81t+oqiL+MdkJIMeA4NXjFW73CefAU0EeMZwlya/Iox1HSWif5aK94yfd64 ZppF3t+XjOtLm6SRSs2gN7zDRPQ1LKKlUaUuPCfPPLGsbyhhKIBoLVXybVs9XTSt m83mtqdRFHeGzrV3oxjmnz1inbFsnzeMN+pwFJG2tDj3EOkNjV/bH7mB9w+Ojkwz qRAfUmWsEVS8WOUkft/etnts3foM7BhsYwsgZIA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1520955561; bh=Bq6Z66VF62gQPV27yqJZwoHslI 9H+z7+bRRChtNy0u4=; b=JTDuLQammdhYMK6t1dAHE7hKU0aEp4DsFMGlOY5FOI 2+3+YZ6XZbSORfEfHmwsjebP2cwyfGPydkkUe7NGEOLn0aC00/4nalIvISecFuiG JTXc4uxpEuv82bm94Pspl+bQXZ32tymJJ0qI2EiiC/LSVcjeZUymVWZ4I68XWe80 hiT0BzeBiueuQvwEAprIfrVCAVQUJ5imjXS4aA3ZpJr5ZlL2sfvGvCjqmGQcZX4J nWCmGx5sliTsvZIHdiQrP4++m3w2TnMfoSmxGb1NhlJGkC5eY/GJsR/bnC9t6G2F 8ycG7lb3Zr0y4i0gghAeq62jdUWHrfFSeZCZtTJFaIUQ== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934649AbeCMPjD (ORCPT ); Tue, 13 Mar 2018 11:39:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35158 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933977AbeCMPjB (ORCPT ); Tue, 13 Mar 2018 11:39:01 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Vacek , Mel Gorman , Michal Hocko , Paul Burton , Pavel Tatashin , Vlastimil Babka , Andrew Morton , Linus Torvalds Subject: [PATCH 4.14 085/140] mm/page_alloc: fix memmap_init_zone pageblock alignment Date: Tue, 13 Mar 2018 16:24:48 +0100 Message-Id: <20180313152503.878363687@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180313152458.201155692@linuxfoundation.org> References: <20180313152458.201155692@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Vacek commit 864b75f9d6b0100bb24fdd9a20d156e7cda9b5ae upstream. Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") introduced a bug where move_freepages() triggers a VM_BUG_ON() on uninitialized page structure due to pageblock alignment. To fix this, simply align the skipped pfns in memmap_init_zone() the same way as in move_freepages_block(). Seen in one of the RHEL reports: crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e rmqueue -e freelist -A1 kernel BUG at mm/page_alloc.c:1389! invalid opcode: 0000 [#1] SMP -- RIP: 0010:[] [] move_freepages+0x15e/0x160 RSP: 0018:ffff88054d727688 EFLAGS: 00010087 -- Call Trace: [] move_freepages_block+0x73/0x80 [] __rmqueue+0x263/0x460 [] get_page_from_freelist+0x7e1/0x9e0 [] __alloc_pages_nodemask+0x176/0x420 -- RIP [] move_freepages+0x15e/0x160 RSP crash> page_init_bug -v | grep RAM 1000 - 9bfff System RAM (620.00 KiB) 100000 - 430bffff System RAM ( 1.05 GiB = 1071.75 MiB = 1097472.00 KiB) 4b0c8000 - 4bf9cfff System RAM ( 14.83 MiB = 15188.00 KiB) 4bfac000 - 646b1fff System RAM (391.02 MiB = 400408.00 KiB) 7b788000 - 7b7fffff System RAM (480.00 KiB) 100000000 - 67fffffff System RAM ( 22.00 GiB) crash> page_init_bug | head -6 7b788000 - 7b7fffff System RAM (480.00 KiB) 1fffff00000000 0 1 DMA32 4096 1048575 505736 505344 505855 0 0 0 DMA 1 4095 1fffff00000400 0 1 DMA32 4096 1048575 BUG, zones differ! Note that this range follows two not populated sections 68000000-77ffffff in this zone. 7b788000-7b7fffff is the first one after a gap. This makes memmap_init_zone() skip all the pfns up to the beginning of this range. But this range is not pageblock (2M) aligned. In fact no range has to be. crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000 PAGE PHYSICAL MAPPING INDEX CNT FLAGS ffffea0001e00000 78000000 0 0 0 0 ffffea0001ed7fc0 7b5ff000 0 0 0 0 ffffea0001ed8000 7b600000 0 0 0 0 <<<< ffffea0001ede1c0 7b787000 0 0 0 0 ffffea0001ede200 7b788000 0 0 1 1fffff00000000 Top part of page flags should contain nodeid and zonenr, which is not the case for page ffffea0001ed8000 here (<<<<). crash> log | grep -o fffea0001ed[^\ ]* | sort -u fffea0001ed8000 fffea0001eded20 fffea0001edffc0 crash> bt -r | grep -o fffea0001ed[^\ ]* | sort -u fffea0001ed8000 fffea0001eded00 fffea0001eded20 fffea0001edffc0 Initialization of the whole beginning of the section is skipped up to the start of the range due to the commit b92df1de5d28. Now any code calling move_freepages_block() (like reusing the page from a freelist as in this example) with a page from the beginning of the range will get the page rounded down to start_page ffffea0001ed8000 and passed to move_freepages() which crashes on assertion getting wrong zonenr. > VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); Note, page_zone() derives the zone from page flags here. >>From similar machine before commit b92df1de5d28: crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000 PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffff73941e00000 78000000 0 0 1 1fffff00000000 fffff73941ed7fc0 7b5ff000 0 0 1 1fffff00000000 fffff73941ed8000 7b600000 0 0 1 1fffff00000000 fffff73941edff80 7b7fe000 0 0 1 1fffff00000000 fffff73941edffc0 7b7ff000 ffff8e67e04d3ae0 ad84 1 1fffff00020068 uptodate,lru,active,mappedtodisk All the pages since the beginning of the section are initialized. move_freepages()' not gonna blow up. The same machine with this fix applied: crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000 PAGE PHYSICAL MAPPING INDEX CNT FLAGS ffffea0001e00000 78000000 0 0 0 0 ffffea0001e00000 7b5ff000 0 0 0 0 ffffea0001ed8000 7b600000 0 0 1 1fffff00000000 ffffea0001edff80 7b7fe000 0 0 1 1fffff00000000 ffffea0001edffc0 7b7ff000 ffff88017fb13720 8 2 1fffff00020068 uptodate,lru,active,mappedtodisk At least the bare minimum of pages is initialized preventing the crash as well. Customers started to report this as soon as 7.4 (where b92df1de5d28 was merged in RHEL) was released. I remember reports from September/October-ish times. It's not easily reproduced and happens on a handful of machines only. I guess that's why. But that does not make it less serious, I think. Though there actually is a report here: https://bugzilla.kernel.org/show_bug.cgi?id=196443 And there are reports for Fedora from July: https://bugzilla.redhat.com/show_bug.cgi?id=1473242 and CentOS: https://bugs.centos.org/view.php?id=13964 and we internally track several dozens reports for RHEL bug https://bugzilla.redhat.com/show_bug.cgi?id=1525121 Link: http://lkml.kernel.org/r/0485727b2e82da7efbce5f6ba42524b429d0391a.1520011945.git.neelx@redhat.com Fixes: b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") Signed-off-by: Daniel Vacek Cc: Mel Gorman Cc: Michal Hocko Cc: Paul Burton Cc: Pavel Tatashin Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_alloc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5307,9 +5307,14 @@ void __meminit memmap_init_zone(unsigned /* * Skip to the pfn preceding the next valid one (or * end_pfn), such that we hit a valid pfn (or end_pfn) - * on our next iteration of the loop. + * on our next iteration of the loop. Note that it needs + * to be pageblock aligned even when the region itself + * is not. move_freepages_block() can shift ahead of + * the valid region but still depends on correct page + * metadata. */ - pfn = memblock_next_valid_pfn(pfn, end_pfn) - 1; + pfn = (memblock_next_valid_pfn(pfn, end_pfn) & + ~(pageblock_nr_pages-1)) - 1; #endif continue; }