INFO: task kworker/0:1:10 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1 state:D stack:20104 pid:10 tgid:10 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events rfkill_global_led_trigger_worker
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
rfkill_global_led_trigger_worker+0x27/0xd0 net/rfkill/core.c:182
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task kworker/0:10:8383 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:10 state:D stack:24328 pid:8383 tgid:8383 ppid:2 task_flags:0x4208060 flags:0x00[ 777.457450][ T38] task:kworker/0:10 state:D stack:24328 pid:8383 tgid:8383 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events rfkill_sync_work
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
device_lock include/linux/device.h:911 [inline]
nfc_dev_down net/nfc/core.c:143 [inline]
nfc_rfkill_set_block+0x50/0x2e0 net/nfc/core.c:179
rfkill_set_block+0x1e5/0x450 net/rfkill/core.c:346
rfkill_sync net/rfkill/core.c:379 [inline]
rfkill_sync_work+0x114/0x200 net/rfkill/core.c:1056
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz.6.240:9335 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.240 state:D stack:24456 pid:9335 tgid:9334 ppid:8338 task_flags:0x40054c flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
hci_unregister_dev+0x374/0x510 net/bluetooth/hci_core.c:2732
vhci_release+0x83/0xe0 drivers/bluetooth/hci_vhci.c:665
__fput+0x45b/0xa80 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6b5/0x2300 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x125e/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9cfd59ebe9
RSP: 002b:00007f9cfb806038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: 0000000000000008 RBX: 00007f9cfd7c5fa0 RCX: 00007f9cfd59ebe9
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000007
RBP: 00007f9cfd621e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9cfd7c6038 R14: 00007f9cfd7c5fa0 R15: 00007fff2d45ddd8
INFO: task syz.9.264:9456 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.264 state:D stack:25080 pid:9456 tgid:9455 ppid:8334 task_flags:0x40054c flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
__flush_work+0x9b9/0xbe0 kernel/workqueue.c:4244
__cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4364
rfkill_unregister+0x95/0x230 net/rfkill/core.c:1139
nfc_unregister_device+0x96/0x2a0 net/nfc/core.c:1167
virtual_ncidev_close+0x59/0x90 drivers/nfc/virtual_ncidev.c:172
__fput+0x45b/0xa80 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6b5/0x2300 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x125e/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f837c82ebe9
RSP: 002b:00007f837aa8e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: 0000000000000009 RBX: 00007f837ca55fa0 RCX: 00007f837c82ebe9
RDX: 0000000000000002 RSI: 0000200000003980 RDI: ffffffffffffff9c
RBP: 00007f837c8b1e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f837ca56038 R14: 00007f837ca55fa0 R15: 00007ffd65db19a8
INFO: task syz-executor:9501 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:28264 pid:9501 tgid:9501 ppid:1 task_flags:0x400040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
rfkill_register+0x37/0x900 net/rfkill/core.c:1071
hci_register_dev+0x3f5/0x830 net/bluetooth/hci_core.c:2631
__vhci_create_device drivers/bluetooth/hci_vhci.c:429 [inline]
vhci_create_device+0x39c/0x6f0 drivers/bluetooth/hci_vhci.c:471
vhci_get_user drivers/bluetooth/hci_vhci.c:528 [inline]
vhci_write+0x3d0/0x4a0 drivers/bluetooth/hci_vhci.c:608
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d2/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4731d3d660
RSP: 002b:00007fffc04e4538 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4731d3d660
RDX: 0000000000000002 RSI: 00007fffc04e454a RDI: 00000000000000ca
RBP: 00007f4731f667b8 R08: 0000000000000000 R09: 00007f4732a9d6c0
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
Showing all locks held in the system:
3 locks held by kworker/0:1/10:
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900000f7bc0 ((work_completion)(&rfkill_global_led_trigger_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900000f7bc0 ((work_completion)(&rfkill_global_led_trigger_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_global_led_trigger_worker+0x27/0xd0 net/rfkill/core.c:182
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:6/1112:
2 locks held by getty/5594:
#0: ffff88823bf3a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/8334:
#0: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
4 locks held by kworker/0:10/8383:
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900040bfbc0 ((work_completion)(&rfkill->sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900040bfbc0 ((work_completion)(&rfkill->sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_sync_work+0x2e/0x200 net/rfkill/core.c:1055
#3: ffff8880365490f0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff8880365490f0 (&dev->mutex){....}-{4:4}, at: nfc_dev_down net/nfc/core.c:143 [inline]
#3: ffff8880365490f0 (&dev->mutex){....}-{4:4}, at: nfc_rfkill_set_block+0x50/0x2e0 net/nfc/core.c:179
1 lock held by syz-executor/8894:
#0: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
4 locks held by kworker/u8:21/9168:
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc9000618fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc9000618fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffffffff8ecc5040 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658
#3: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
1 lock held by syz.6.240/9335:
#0: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
2 locks held by syz-executor/9431:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
#1: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_fop_open+0x138/0x820 net/rfkill/core.c:1178
1 lock held by syz.9.264/9456:
#0: ffff8880365490f0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#0: ffff8880365490f0 (&dev->mutex){....}-{4:4}, at: nfc_unregister_device+0x63/0x2a0 net/nfc/core.c:1165
2 locks held by syz-executor/9501:
#0: ffff888053c10988 (&data->open_mutex){+.+.}-{4:4}, at: vhci_create_device+0x34/0x6f0 drivers/bluetooth/hci_vhci.c:470
#1: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_register+0x37/0x900 net/rfkill/core.c:1071
2 locks held by syz-executor/9596:
#0: ffff8880548d4988 (&data->open_mutex){+.+.}-{4:4}, at: vhci_create_device+0x34/0x6f0 drivers/bluetooth/hci_vhci.c:470
#1: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_register+0x37/0x900 net/rfkill/core.c:1071
2 locks held by syz-executor/9634:
#0: ffff888033f0e188 (&data->open_mutex){+.+.}-{4:4}, at: vhci_create_device+0x34/0x6f0 drivers/bluetooth/hci_vhci.c:470
#1: ffffffff8efb0518 (rfkill_global_mutex){+.+.}-{4:4}, at: rfkill_register+0x37/0x900 net/rfkill/core.c:1071
1 lock held by syz.8.288/9741:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/9941:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/10283:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/10373:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/10527:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/10557:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/10912:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/11203:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/11277:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/11435:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
1 lock held by syz-executor/11465:
#0: ffffffff8e216d18 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x340 drivers/char/misc.c:125
2 locks held by dhcpcd-run-hook/11665:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:io_serial_out+0x0/0xc0 drivers/tty/serial/8250/8250_port.c:404
Code: ad 20 8e 4c 89 fa e8 af 26 b0 ff eb 9f 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 54 53 89 d3 89 f5 49 89 fe 49 bc 00
RSP: 0018:ffffc90000167918 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff993a7540 RCX: dffffc0000000000
RDX: 0000000000000034 RSI: 0000000000000000 RDI: ffffffff993a7540
RBP: ffffc90000167a90 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff853ea930 R12: 0000000000000034
R13: 0000000000000001 R14: ffffffff9905194f R15: ffffffff9905194e
FS: 0000000000000000(0000) GS:ffff8881269c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056179553f660 CR3: 000000000d7a6000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:798 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3246 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x1291/0x1b40 drivers/tty/serial/8250/8250_port.c:3396
console_emit_next_record kernel/printk/printk.c:3118 [inline]
console_flush_all+0x695/0xcd0 kernel/printk/printk.c:3226
__console_flush_and_unlock+0xa4/0x240 kernel/printk/printk.c:3285
legacy_kthread_func+0x13b/0x1a0 kernel/printk/printk.c:3638
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245