INFO: task systemd-shutdow:1 blocked for more than 143 seconds.
      Not tainted 5.11.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:systemd-shutdow state:D stack:22904 pid:    1 ppid:     0 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4327 [inline]
 __schedule+0x91b/0x1f90 kernel/sched/core.c:5078
 schedule+0xcb/0x270 kernel/sched/core.c:5157
 wait_for_device_probe+0x1be/0x220 drivers/base/dd.c:704
 device_shutdown+0x18/0x5c0 drivers/base/core.c:4180
 kernel_restart_prepare kernel/reboot.c:76 [inline]
 kernel_restart+0x61/0xa0 kernel/reboot.c:246
 __do_sys_reboot+0x31e/0x3e0 kernel/reboot.c:349
 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fb2e9ac88c6
RSP: 002b:00007ffd6f902b98 EFLAGS: 00000202 ORIG_RAX: 00000000000000a9
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb2e9ac88c6
RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead
RBP: 00007ffd6f902c28 R08: 0000000000002800 R09: 0000000000000005
R10: 0000000000000002 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 00005594ce7e0150 R15: 00007ffd6f902f18

Showing all locks held in the system:
1 lock held by systemd-shutdow/1:
 #0: ffffffff87952f08 (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x1a3/0x3e0 kernel/reboot.c:346
1 lock held by khungtaskd/1269:
 #0: ffffffff87a784a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:6259
5 locks held by kworker/1:3/6710:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1269 Comm: khungtaskd Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x46/0xe0 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1da/0x200 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd32/0xf70 kernel/hung_task.c:294
 kthread+0x38c/0x460 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:110 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:516