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: 0010:[<ffffffff816dbd63>] [<ffffffff816dbd63>] reserve_bootmem_region+0x6a/0xef RSP: 0000:ffffffff81c03eb0 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffffff81c03ec0 RSI: ffffffff81d205c0 RDI: ffffffff8213ee60 R13: ffffea0000000000 R14: ffffea0000000020 R15: ffffea0000000020 FS: 0000000000000000(0000) GS:ffff8800fba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000002a3c8 CR3: 0000000001c06000 CR4: 00000000000006b0 Stack: ffffffff81c03f00 0000000000000400 ffff8800fbfc3200 ffffffff81e2a2c0 ffffffff81c03fb0 ffffffff81c03f20 ffffffff81dadf7d ffffea0002000040 ffffea0000000000 0000000000000000 000000000000ffff 0000000000000001 Call Trace: [<ffffffff81dadf7d>] free_all_bootmem+0x4b/0x12a [<ffffffff81d97122>] mem_init+0x70/0xa3 [<ffffffff81d78f21>] 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. Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # 4.2+ --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a19527aa4243..5a616de1adca 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1097,7 +1097,7 @@ 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; -- 2.6.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>