linux-kernel - [PATCH] metag: Drop show_mem() from mem

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Message-ID: <20160805121704.32198-1-james.hogan@imgtec.com>
Date:	Fri, 5 Aug 2016 13:17:04 +0100
From:	James Hogan <james.hogan@...tec.com>
To:	<linux-metag@...r.kernel.org>
CC:	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
	James Hogan <james.hogan@...tec.com>,
	Mel Gorman <mgorman@...hsingularity.net>
Subject: [PATCH] metag: Drop show_mem() from mem_init()

The recent commit 599d0c954f91 ("mm, vmscan: move LRU lists to node"),
changed memory management code so that show_mem() is no longer safe to
call prior to setup_per_cpu_pageset(), as pgdat->per_cpu_nodestats will
still be NULL. This causes an oops on metag due to the call to
show_mem() from mem_init():

  node_page_state_snapshot(...) + 0x48
  pgdat_reclaimable(struct pglist_data * pgdat = 0x402517a0)
  show_free_areas(unsigned int filter = 0) + 0x2cc
  show_mem(unsigned int filter = 0) + 0x18
  mem_init()
  mm_init()
  start_kernel() + 0x204

This wasn't a problem before with zone_reclaimable() as zone_pcp_init()
was already setting zone->pageset to &boot_pageset, via setup_arch() and
paging_init(), which happens before mm_init():

  zone_pcp_init(...)
  free_area_init_core(...) + 0x138
  free_area_init_node(int nid = 0, ...) + 0x1a0
  free_area_init_nodes(...) + 0x440
  paging_init(unsigned long mem_end = 0x4fe00000) + 0x378
  setup_arch(char ** cmdline_p = 0x4024e038) + 0x2b8
  start_kernel() + 0x54

No other arches appear to call show_mem() during boot, and it doesn't
really add much value to the log, so lets just drop it from mem_init().

Signed-off-by: James Hogan <james.hogan@...tec.com>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: linux-metag@...r.kernel.org
---
 arch/metag/mm/init.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/metag/mm/init.c b/arch/metag/mm/init.c
index 11fa51c89617..c0ec116b3993 100644
--- a/arch/metag/mm/init.c
+++ b/arch/metag/mm/init.c
@@ -390,7 +390,6 @@ void __init mem_init(void)
 
 	free_all_bootmem();
 	mem_init_print_info(NULL);
-	show_mem(0);
 }
 
 void free_initmem(void)
-- 
2.9.2