INFO: task poweroff:5484 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:poweroff        state:D stack:22912 pid:5484  tgid:5484  ppid:5280   task_flags:0x400000 flags:0x00004002
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7e6/0x1350
 sync_bdevs+0x1ac/0x340
 ksys_sync+0xb9/0x150
 __ia32_sys_sync+0xe/0x20
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd9cd7ae7e7
RSP: 002b:00007fffa14e0208 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fd9cd7ae7e7
RDX: 0000000000000078 RSI: 00007fd9cd93d8ca RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000001 R09: 00007fd9cd93d8ca
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffa14e0358
R13: 00007fffa14e0368 R14: 0000561f1de1b169 R15: 00007fd9cd98ea80
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11778 Comm: syz.3.3598 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__free_one_page+0x116/0xbd0
Code: 4c 89 f6 e8 0c f7 00 00 84 c0 0f 85 cd 09 00 00 41 83 fd 20 0f 83 6f 08 00 00 48 c7 c0 70 b4 a3 8f 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 70 08 00 00 83 3d ab 07 8e 0d 00 74 19 48 8d bd 18 06
RSP: 0018:ffffc900062af720 EFLAGS: 00000806
RAX: 0000000000000000 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8be33660 RDI: ffffffff8be33620
RBP: ffff88805fffbb80 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f47067 R12: 0000000000000000
R13: 0000000000000000 R14: ffffea0000d9a480 R15: dffffc0000000000
FS:  00007f33e3e606c0(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33e3e3efc8 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 free_pcppages_bulk+0x2da/0x4e0
 free_frozen_page_commit+0x62c/0x1070
 __free_frozen_pages+0x67f/0xd30
 vfree+0x25a/0x400
 kcov_close+0x28/0x50
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f33e2fc14a5
Code: Unable to access opcode bytes at 0x7f33e2fc147b.
RSP: 002b:00007f33e3e5ff80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f33e31b5fa0 RCX: 00007f33e2fc14a5
RDX: 00007f33e3e5ffc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f33e3011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f33e31b6038 R14: 00007f33e31b5fa0 R15: 00007fff1fc5e738
 </TASK>
