FYI, we noticed the below changes on

git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
commit c1c2ee950beab73909ab0dbeb75a235e174d5301 ("mm: meminit: reduce number of times pageblocks are set during struct page init")


+----------------------+------------+------------+
|                      | 8abe0b240f | c1c2ee950b |
+----------------------+------------+------------+
| boot_successes       | 22         | 0          |
| early-boot-hang      | 1          |            |
| boot_failures        | 0          | 10         |
| BUG:kernel_boot_hang | 0          | 10         |
+----------------------+------------+------------+


[    0.000000] On node 0 totalpages: 92030
[    0.000000]   DMA zone: 64 pages used for memmap
[    0.000000]   DMA zone: 21 pages reserved
[    0.000000]   DMA zone: 3998 pages, LIFO batch:0
[    0.000000]   DMA32 zone: 1376 pages used for memmap
[    0.000000]   DMA32 zone: 88032 pages, LIFO batch:15
[    0.000000] page:ffffea0000040000 count:0 mapcount:1 mapping:          (null) index:0x0
[    0.000000] flags: 0x0()
[    0.000000] page dumped because: VM_BUG_ON_PAGE(!zone_spans_pfn(zone, pfn))
PANIC: early exception 06 rip 10:ffffffff811de134 error 0 cr2 ffff880005728000
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.1.0-rc1-00171-gc1c2ee9 #1
[    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[    0.000000]  ffffea0000040000 ffffffff82ed7c80 ffffffff8235d9a5 00000000000003f8
[    0.000000]  0000000000000010 ffffffff82ed7d68 ffffffff840261b0 0000000000000000
[    0.000000]  000000000000047b 0000000000000000 0000000000000001 0000000000000006
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff8235d9a5>] dump_stack+0xa0/0xd5
[    0.000000]  [<ffffffff840261b0>] early_idt_handler+0x90/0xb7
[    0.000000]  [<ffffffff81120c58>] ? up+0x55/0x61
[    0.000000]  [<ffffffff811de134>] ? set_pfnblock_flags_mask+0x9a/0x100
[    0.000000]  [<ffffffff811de12d>] ? set_pfnblock_flags_mask+0x93/0x100
[    0.000000]  [<ffffffff811de1ec>] set_pageblock_migratetype+0x52/0x5b
[    0.000000]  [<ffffffff840d30b5>] memmap_init_zone+0xf8/0x168
[    0.000000]  [<ffffffff840d35a3>] free_area_init_node+0x47e/0x4e5
[    0.000000]  [<ffffffff8405fb3a>] free_area_init_nodes+0x30e/0x35e
[    0.000000]  [<ffffffff8404911a>] zone_sizes_init+0x57/0x60
[    0.000000]  [<ffffffff840495c8>] paging_init+0x4a/0x53
[    0.000000]  [<ffffffff840312d8>] setup_arch+0x10e9/0x126a
[    0.000000]  [<ffffffff81131c31>] ? vprintk_default+0x24/0x2d
[    0.000000]  [<ffffffff84026120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff840270c3>] start_kernel+0x141/0x7c3
[    0.000000]  [<ffffffff84026120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff840265a9>] x86_64_start_reservations+0x46/0x4f
[    0.000000]  [<ffffffff84026789>] x86_64_start_kernel+0x1d7/0x1ed
[    0.000000] RIP 0x0

Thanks,
Ying Huang