From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f69.google.com (mail-lf0-f69.google.com [209.85.215.69]) by kanga.kvack.org (Postfix) with ESMTP id A05AB6B0253 for ; Fri, 5 Aug 2016 11:53:29 -0400 (EDT) Received: by mail-lf0-f69.google.com with SMTP id 33so155735938lfw.1 for ; Fri, 05 Aug 2016 08:53:29 -0700 (PDT) Received: from outbound-smtp05.blacknight.com (outbound-smtp05.blacknight.com. [81.17.249.38]) by mx.google.com with ESMTPS id t124si3336811wmg.26.2016.08.05.01.41.17 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 05 Aug 2016 01:41:17 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp05.blacknight.com (Postfix) with ESMTPS id 3456398DAA for ; Fri, 5 Aug 2016 08:41:17 +0000 (UTC) Date: Fri, 5 Aug 2016 09:41:15 +0100 From: Mel Gorman Subject: Re: [PATCH 03/34] mm, vmscan: move LRU lists to node Message-ID: <20160805084115.GO2799@techsingularity.net> References: <1467970510-21195-1-git-send-email-mgorman@techsingularity.net> <1467970510-21195-4-git-send-email-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: James Hogan Cc: Andrew Morton , Linux-MM , Rik van Riel , Vlastimil Babka , Johannes Weiner , Minchan Kim , Joonsoo Kim , LKML , metag On Thu, Aug 04, 2016 at 09:59:17PM +0100, James Hogan wrote: > > Signed-off-by: Mel Gorman > > Acked-by: Johannes Weiner > > Acked-by: Vlastimil Babka > > This breaks boot on metag architecture: > Oops: err 0007 (Data access general read/write fault) addr 00233008 [#1] > > It appears to be in node_page_state_snapshot() (via > pgdat_reclaimable()), and have come via mm_init. Here's the relevant > bit of the backtrace: > > node_page_state_snapshot@0x4009c884(enum node_stat_item item = > ???, struct pglist_data * pgdat = ???) + 0x48 > pgdat_reclaimable(struct pglist_data * pgdat = 0x402517a0) > show_free_areas(unsigned int filter = 0) + 0x2cc > show_mem(unsigned int filter = 0) + 0x18 > mm_init@0x4025c3d4() > start_kernel() + 0x204 > > __per_cpu_offset[0] == 0x233000 (close to bad addr), > pgdat->per_cpu_nodestats = NULL. and setup_per_cpu_pageset() > definitely hasn't been called yet (mm_init is called before > setup_per_cpu_pageset()). > > Any ideas what the correct solution is (and why presumably others > haven't seen the same issue on other architectures?). > metag calls show_mem in mem_init() before the pagesets are initialised. What's surprising is that it worked for the zone stats as it appears that calling zone_reclaimable() from that context should also have broken. Did anything change recently that would have avoided the zone->pageset dereference in zone_reclaimable() before? The easiest option would be to not call show_mem from arch code until after the pagesets are setup. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org