[linux-next] kernel panic when poweroff (Tree for Dec 11)

[Hui Su]

Hi,all:

I compile the next tree today(Tree for Dec 11) with x86_64_defconfig,
then run the kernel with cmd:
sudo qemu-system-x86_64 \                                            
	-kernel /home/ubuntu/workspace/share/next/bzImage \                     
	-hda /home/ubuntu/myspace/qemu_build/ubuntu.img \                       
	-hdb /home/ubuntu/myspace/qemu_build/init.img   \                       
	-append "root=/dev/sda console=ttyS0 crashkernel=128M" \                
	-nographic \                                                            
	-m 1024 \                                                               
	-fsdev local,id=fs1,path=/home/ubuntu/workspace/share,security_model=none \
	-device virtio-9p-pci,fsdev=fs1,mount_tag=host_share' 

it goes well, but when it poweroff, the panic came like this:
[  OK  ] Reached target Power-Off.
[  273.685905] BUG: unable to handle page fault for address: ffffffffffffffe8
[  273.695330] #PF: supervisor read access in kernel mode
[  273.696944] #PF: error_code(0x0000) - not-present page
[  273.698303] PGD 1140f067 P4D 1140f067 PUD 11411067 PMD 0 
[  273.700358] Oops: 0000 [#1] SMP NOPTI
[  273.701682] CPU: 0 PID: 1 Comm: shutdown Not tainted 5.10.0-rc7-next-20201211 #2
[  273.704130] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[  273.706446] RIP: 0010:platform_shutdown+0x4/0x20
[  273.709430] Code: 84 00 00 00 00 00 48 81 fe 60 23 99 99 74 05 0f b7 46 08 c3 31 c0 83 bf 78 02 00 00 ff 75 f0 c3 66 0f 1f 44 00 00 48 8b 47 68 <48> 8b 40 e8f
[  273.712017] RSP: 0018:ffffaf9f00013dd8 EFLAGS: 00000246
[  273.714486] RAX: 0000000000000000 RBX: ffff9b16012f3c18 RCX: 0000000000000000
[  273.715641] RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffff9b16012f3c10
[  273.717263] RBP: ffffffff999923a0 R08: 0000000000000000 R09: 0000000000000000
[  273.719634] R10: ffff9b163fc29100 R11: 0000000000000400 R12: ffff9b16012f3c10
[  273.720744] R13: ffff9b16012f3c90 R14: 00000000fee1dead R15: 0000000000000000
[  273.727288] FS:  00007f8190b8b980(0000) GS:ffff9b163fc00000(0000) knlGS:0000000000000000
[  273.728787] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  273.729710] CR2: ffffffffffffffe8 CR3: 0000000001fd4000 CR4: 00000000000006f0
[  273.730887] Call Trace:
[  273.732286]  device_shutdown+0x14a/0x1b0
[  273.734269]  kernel_power_off+0x2c/0x70
[  273.736045]  __do_sys_reboot+0x126/0x210
[  273.736663]  ? do_sigtimedwait.isra.0+0x1c9/0x1f0
[  273.737478]  ? __x64_sys_rt_sigtimedwait+0x69/0xd0
[  273.738024]  ? do_writev+0x66/0x110
[  273.742951]  ? exit_to_user_mode_prepare+0x2f/0x130
[  273.743753]  do_syscall_64+0x33/0x40
[  273.744333]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  273.745225] RIP: 0033:0x7f8191a39487
[  273.746531] Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 89 fa be 69 19 12 28 bf ad de e1 fe b8 a9 00 00 00 0f 05 <48> 3d 00 f08
[  273.749501] RSP: 002b:00007fff89b2aac8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9
[  273.750640] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8191a39487
[  273.751767] RDX: 000000004321fedc RSI: 0000000028121969 RDI: 00000000fee1dead
[  273.755119] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fff89b29ed0
[  273.756097] R10: 00007f8190b8b900 R11: 0000000000000202 R12: 0000000000000000
[  273.757119] R13: 0000000000000000 R14: 0000001b00000004 R15: 0000000000000001
[  273.758191] Modules linked in:
[  273.759203] CR2: ffffffffffffffe8
[  273.821684] ---[ end trace 96d41b084dff3b81 ]---
[  273.830228] RIP: 0010:platform_shutdown+0x4/0x20
[  273.837431] Code: 84 00 00 00 00 00 48 81 fe 60 23 99 99 74 05 0f b7 46 08 c3 31 c0 83 bf 78 02 00 00 ff 75 f0 c3 66 0f 1f 44 00 00 48 8b 47 68 <48> 8b 40 e8f
[  273.849655] RSP: 0018:ffffaf9f00013dd8 EFLAGS: 00000246
[  273.852108] RAX: 0000000000000000 RBX: ffff9b16012f3c18 RCX: 0000000000000000
[  273.853109] RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffff9b16012f3c10
[  273.854291] RBP: ffffffff999923a0 R08: 0000000000000000 R09: 0000000000000000
[  273.855301] R10: ffff9b163fc29100 R11: 0000000000000400 R12: ffff9b16012f3c10
[  273.856067] R13: ffff9b16012f3c90 R14: 00000000fee1dead R15: 0000000000000000
[  273.856846] FS:  00007f8190b8b980(0000) GS:ffff9b163fc00000(0000) knlGS:0000000000000000
[  273.858692] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  273.859415] CR2: ffffffffffffffe8 CR3: 0000000001fd4000 CR4: 00000000000006f0
[  273.860824] Kernel panic - not syncing: Attempted to kill init!  exitcode=0x00000009
[  273.868488] Kernel Offset: 0x17800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[  273.871837] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 ]---
qemu-system-x86_64: terminating on signal 15 from pid 2836242 (pkill)

The next tree for Dec 10 does not contain this problem, and the tree for Dec 11
can reproduce this problem stably(always panic when poweroff).

Reported-by: Hui Su <sh_def@xxxxxxx>