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authorMel Gorman <mgorman@techsingularity.net>2016-07-14 12:07:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-15 14:54:27 +0900
commite4568d3803852d00effd41dcdd489e726b998879 (patch)
tree87798a496136f5dd1896dfa203212b42ab18ee23 /mm
parent0ab686d8c8303069e80300663b3be6201a8697fb (diff)
downloadlinux-e4568d3803852d00effd41dcdd489e726b998879.tar.gz
mm, meminit: always return a valid node from early_pfn_to_nid
early_pfn_to_nid can return node 0 if a PFN is invalid on machines that
has no node 0.  A machine with only node 1 was observed to crash with
the following message:

   BUG: unable to handle kernel paging request at 000000000002a3c8
   PGD 0
   Modules linked in:
   Hardware name: Supermicro H8DSP-8/H8DSP-8, BIOS 080011  06/30/2006
   task: ffffffff81c0d500 ti: ffffffff81c00000 task.ti: ffffffff81c00000
   RIP: reserve_bootmem_region+0x6a/0xef
   CR2: 000000000002a3c8 CR3: 0000000001c06000 CR4: 00000000000006b0
   Call Trace:
      free_all_bootmem+0x4b/0x12a
      mem_init+0x70/0xa3
      start_kernel+0x25b/0x49b

The problem is that early_page_uninitialised uses the early_pfn_to_nid
helper which returns node 0 for invalid PFNs.  No caller of
early_pfn_to_nid cares except early_page_uninitialised.  This patch has
early_pfn_to_nid always return a valid node.

Link: http://lkml.kernel.org/r/1468008031-3848-3-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6903b695ebae..5d013526bd0a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1273,7 +1273,7 @@ int __meminit early_pfn_to_nid(unsigned long pfn)
 	spin_lock(&early_pfn_lock);
 	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
 	if (nid < 0)
-		nid = 0;
+		nid = first_online_node;
 	spin_unlock(&early_pfn_lock);
 
 	return nid;