FYI, we noticed the following commit:

https://github.com/0day-ci/linux Chris-Wilson/mm-vmalloc-Replace-opencoded-4-level-page-walkers/20161015-171049
commit 95bc4368c70a2dd0a1837b1f50c9ab0cdf243066 ("mm/vmalloc: Replace opencoded 4-level page walkers")

in testcase: boot

on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 2G

caused below changes:


+----------------------------------------------------------------------------+------------+------------+
|                                                                            | fe4cd888f7 | 95bc4368c7 |
+----------------------------------------------------------------------------+------------+------------+
| boot_successes                                                             | 10         | 0          |
| boot_failures                                                              | 4          | 16         |
| Kernel_panic-not_syncing:VFS:Unable_to_mount_root_fs_on_unknown-block(#,#) | 2          |            |
| calltrace:prepare_namespace                                                | 2          |            |
| BUG:kernel_reboot-without-warning_in_test_stage                            | 2          |            |
| kernel_BUG_at_mm/memory.c                                                  | 0          | 16         |
| RIP:apply_to_page_range                                                    | 0          | 16         |
| calltrace:bochs_init                                                       | 0          | 16         |
| Kernel_panic-not_syncing:Fatal_exception                                   | 0          | 16         |
+----------------------------------------------------------------------------+------------+------------+



[    4.127462] [TTM] Initializing pool allocator
[    4.127892] [TTM] Initializing DMA pool allocator
[    4.130333] ------------[ cut here ]------------
[    4.130788] kernel BUG at mm/memory.c:1881!
[    4.131360] invalid opcode: 0000 [#1]
[    4.131711] CPU: 0 PID: 1 Comm: swapper Not tainted 4.8.0-mm1-00158-g95bc436 #1
[    4.132403] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[    4.133240] task: ffff9ac080060000 task.stack: ffffba2c80008000
[    4.133799] RIP: 0010:[<ffffffffb8704b63>]  [<ffffffffb8704b63>] apply_to_page_range+0x1dc/0x2b4
[    4.134636] RSP: 0000:ffffba2c8000b7b8  EFLAGS: 00010202
[    4.135136] RAX: 0000000000000001 RBX: ffffba2c81800000 RCX: 00003ffffffff000
[    4.135799] RDX: 00003fffffe00000 RSI: ffff9ac080000000 RDI: 80000000fd0001f3
[    4.136467] RBP: ffffba2c8000b848 R08: 0000000000000000 R09: b0ec37a96c1e6fac
[    4.137135] R10: 0000000000000000 R11: ffff9ac0800607e0 R12: ffff9ac080013060
[    4.137795] R13: ffff9ac0f0a809a8 R14: ffff9ac17d000000 R15: ffffffffb9a04060
[    4.138461] FS:  0000000000000000(0000) GS:ffffffffb981f000(0000) knlGS:0000000000000000
[    4.139215] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    4.139750] CR2: 0000000000000000 CR3: 000000005d40c000 CR4: 00000000001406b0
[    4.140417] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    4.141081] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    4.141739] Stack:
[    4.141933]  ffffba2c81b00fff ffffba2c81b00fff ffffba2c81b00fff 0000000000000000
[    4.142662]  ffffffffb870d8e3 ffffba2c8000b7f0 0000000000000246 ffffffffb980cba0
[    4.143389]  ffff9ac080012590 ffffba2c81b01000 ffffba2c81a00000 ffffba2c81b01000
[    4.144113] Call Trace:
[    4.144349]  [<ffffffffb870d8e3>] ? vmap_page+0xa5/0xa5
[    4.144835]  [<ffffffffb870d59e>] vunmap_page_range+0x23/0x25
[    4.145375]  [<ffffffffb870ebc2>] remove_vm_area+0x6c/0x7c
[    4.145886]  [<ffffffffb86201e8>] iounmap+0x86/0x9f
[    4.146347]  [<ffffffffb8aa22a4>] ttm_mem_reg_iounmap+0x32/0x56
[    4.146898]  [<ffffffffb8aa2727>] ttm_bo_move_memcpy+0x357/0x396
[    4.147461]  [<ffffffffb8aa0346>] ttm_bo_handle_move_mem+0x1e5/0x325
[    4.148058]  [<ffffffffb8aa0bbd>] ? ttm_bo_mem_space+0x147/0x353
[    4.148620]  [<ffffffffb8aa1130>] ttm_bo_validate+0xe9/0x14f
[    4.149156]  [<ffffffffb8d1ca59>] bochs_bo_pin+0x109/0x133
[    4.149670]  [<ffffffffb8d1d463>] bochsfb_create+0xfd/0x2a8
[    4.150197]  [<ffffffffb8a80419>] drm_fb_helper_initial_config+0x25f/0x328
[    4.150839]  [<ffffffffb8d1d671>] bochs_fbdev_init+0x63/0x86
[    4.151375]  [<ffffffffb8d1c535>] bochs_load+0x6f/0x83
[    4.151858]  [<ffffffffb8a89278>] drm_dev_register+0x81/0xc2
[    4.152394]  [<ffffffffb8a8a4dc>] drm_get_pci_dev+0xe5/0x19b
[    4.152926]  [<ffffffffb8d1c4bf>] bochs_pci_probe+0xd3/0xda
[    4.153454]  [<ffffffffb8948b68>] pci_device_probe+0x6b/0xc2
[    4.153986]  [<ffffffffb8d2ace8>] driver_probe_device+0x196/0x34e
[    4.154559]  [<ffffffffb8d2aea0>] ? driver_probe_device+0x34e/0x34e
[    4.155146]  [<ffffffffb8d2af4c>] __driver_attach+0xac/0xce
[    4.155667]  [<ffffffffb8d291d4>] bus_for_each_dev+0x6a/0x82
[    4.156199]  [<ffffffffb8d2b17f>] driver_attach+0x19/0x1b
[    4.156705]  [<ffffffffb8d29a4e>] bus_add_driver+0x134/0x218
[    4.157240]  [<ffffffffb8d2b599>] driver_register+0x83/0xba
[    4.157761]  [<ffffffffb89489c4>] __pci_register_driver+0x58/0x5b
[    4.158334]  [<ffffffffb9b803a5>] ? qxl_init+0x34/0x34
[    4.158815]  [<ffffffffb8a8a5d9>] drm_pci_init+0x47/0xc8
[    4.159317]  [<ffffffffb9b803a5>] ? qxl_init+0x34/0x34
[    4.159801]  [<ffffffffb9b4d87a>] ? set_debug_rodata+0x12/0x12
[    4.160350]  [<ffffffffb9b803bc>] bochs_init+0x17/0x19
[    4.160832]  [<ffffffffb9b4df7a>] do_one_initcall+0x89/0x116
[    4.161367]  [<ffffffffb9b4d87a>] ? set_debug_rodata+0x12/0x12
[    4.161914]  [<ffffffffb9b4e1b8>] kernel_init_freeable+0x1b1/0x23e
[    4.162498]  [<ffffffffb8fff197>] ? rest_init+0x12e/0x12e
[    4.163003]  [<ffffffffb8fff1a0>] kernel_init+0x9/0xe6
[    4.163493]  [<ffffffffb9004fea>] ret_from_fork+0x2a/0x40
[    4.163997] Code: da 4c 89 e6 4c 89 ff e8 03 dc ff ff 85 c0 74 cd e9 da 00 00 00 4d 85 f6 0f 84 d1 00 00 00 49 8b 3c 24 e8 21 fa f1 ff 85 c0 74 02 <0f> 0b e8 c1 c6 ff ff 49 8b 3c 24 e8 84 c6 ff ff 41 f6 04 24 80 
[    4.166406] RIP  [<ffffffffb8704b63>] apply_to_page_range+0x1dc/0x2b4
[    4.167016]  RSP <ffffba2c8000b7b8>
[    4.167360] ---[ end trace 5547b6d060f4198f ]---
[    4.167802] Kernel panic - not syncing: Fatal exception





Thanks,
Kernel Test Robot