From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id E35346B0006 for ; Mon, 12 Mar 2018 08:26:58 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id w140so7965521qkb.15 for ; Mon, 12 Mar 2018 05:26:58 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id x94sor4593369qte.143.2018.03.12.05.26.57 for (Google Transport Security); Mon, 12 Mar 2018 05:26:57 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1519908465-12328-1-git-send-email-neelx@redhat.com> <0485727b2e82da7efbce5f6ba42524b429d0391a.1520011945.git.neelx@redhat.com> <20180302164052.5eea1b896e3a7125d1e1f23a@linux-foundation.org> From: Sudeep Holla Date: Mon, 12 Mar 2018 12:26:56 +0000 Message-ID: Subject: Re: [PATCH v3 2/2] mm/page_alloc: fix memmap_init_zone pageblock alignment Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Vacek Cc: Andrew Morton , open list , linux-mm@kvack.org, Michal Hocko , Vlastimil Babka , Mel Gorman , Pavel Tatashin , Paul Burton , stable@vger.kernel.org, Sudeep Holla Hi, I couldn't find the exact mail corresponding to the patch merged in v4.16-rc5 but commit 864b75f9d6b01 "mm/page_alloc: fix memmap_init_zone pageblock alignment" cause boot hang on my ARM64 platform. Log: [ 0.000000] NUMA: No NUMA configuration found [ 0.000000] NUMA: Faking a node at [mem 0x0000000000000000-0x00000009ffffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x9fffcb480-0x9fffccf7f] [ 0.000000] Zone ranges: [ 0.000000] DMA32 [mem 0x0000000080000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x00000009ffffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000080000000-0x00000000f8f9afff] [ 0.000000] node 0: [mem 0x00000000f8f9b000-0x00000000f908ffff] [ 0.000000] node 0: [mem 0x00000000f9090000-0x00000000f914ffff] [ 0.000000] node 0: [mem 0x00000000f9150000-0x00000000f920ffff] [ 0.000000] node 0: [mem 0x00000000f9210000-0x00000000f922ffff] [ 0.000000] node 0: [mem 0x00000000f9230000-0x00000000f95bffff] [ 0.000000] node 0: [mem 0x00000000f95c0000-0x00000000fe58ffff] [ 0.000000] node 0: [mem 0x00000000fe590000-0x00000000fe5cffff] [ 0.000000] node 0: [mem 0x00000000fe5d0000-0x00000000fe5dffff] [ 0.000000] node 0: [mem 0x00000000fe5e0000-0x00000000fe62ffff] [ 0.000000] node 0: [mem 0x00000000fe630000-0x00000000feffffff] [ 0.000000] node 0: [mem 0x0000000880000000-0x00000009ffffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000080000000-0x00000009ffffffff] On Sat, Mar 3, 2018 at 1:08 AM, Daniel Vacek wrote: > On Sat, Mar 3, 2018 at 1:40 AM, Andrew Morton wrote: >> On Sat, 3 Mar 2018 01:12:26 +0100 Daniel Vacek wrote: >> >>> 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. >> >> b92df1de5d28 was merged a year ago. Can you suggest why this hasn't >> been reported before now? > > Yeah. I was surprised myself I couldn't find a fix to backport to > RHEL. But actually 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 > > Enough? ;-) > >> This makes me wonder whether a -stable backport is really needed... > > For some machines it definitely is. Won't hurt either, IMHO. > > --nX