INFO: task syz.5.668:8183 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.668 state:D stack:25368 pid:8183 tgid:8182 ppid:7469 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5830 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7531
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
bdev_release+0x1b8/0x690 block/bdev.c:1173
blkdev_release+0x15/0x20 block/fops.c:695
__fput+0x408/0xa40 fs/file_table.c:513
task_work_run+0x1d9/0x260 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f392739f559
RSP: 002b:00007f3928286028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f3927625fa0 RCX: 00007f392739f559
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f3927436b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3927626038 R14: 00007f3927625fa0 R15: 00007ffe0534f368
Showing all locks held in the system:
locks held by pr/ttyS0/34: 2, last CPU#0:
#0: ffffffff90033f58 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff90033f58 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:493 [inline]
#0: ffffffff90033f58 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
#1: ffff8880b8226498 (&base->lock){-.-.}-{2:2}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffff8880b8226498 (&base->lock){-.-.}-{2:2}, at: rcu_do_batch kernel/rcu/tree.c:2644 [inline]
#1: ffff8880b8226498 (&base->lock){-.-.}-{2:2}, at: rcu_core+0x8b0/0x1230 kernel/rcu/tree.c:2919
locks held by khungtaskd/35: 1, last CPU#1:
#0: ffffffff9015a460 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015a460 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015a460 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/1:2/1226: 12, on CPU#1:
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc9000572fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000572fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000572fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc9000572fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802b81b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#2: ffff88802b81b1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff888054b341d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#3: ffff888054b341d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1106
#4: ffff8880276631a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#4: ffff8880276631a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1106
#5: ffff888036d04260 (&dev->clientlist_mutex){+.+.}-{4:4}, at: drm_client_register+0x4b/0x200 drivers/gpu/drm/drm_client.c:129
#6: ffff888035fa8270
(&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_initial_config+0x46/0x80 drivers/gpu/drm/clients/drm_fbdev_helper.c:1778
#7: ffff888035fa8090 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_probe+0x42f/0x60c0 drivers/gpu/drm/drm_client_modeset.c:865
#8: ffff888036d043f8 (&dev->mode_config.mutex){+.+.}-{4:4}, at: drm_client_modeset_probe+0x44a/0x60c0 drivers/gpu/drm/drm_client_modeset.c:867
#9: ffffc9000572e6f0 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_helper_probe_single_connector_modes+0x17c/0x1a60 drivers/gpu/drm/drm_probe_helper.c:571
#10: ffffc9000572e718 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_helper_probe_single_connector_modes+0x17c/0x1a60 drivers/gpu/drm/drm_probe_helper.c:571
#11: ffffffff90b169f8 (drm_unplug_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:213 [inline]
#11: ffffffff90b169f8 (drm_unplug_srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:320 [inline]
#11: ffffffff90b169f8 (drm_unplug_srcu){.+.+}-{0:0}, at: drm_dev_enter+0x49/0x150 drivers/gpu/drm/drm_drv.c:455
locks held by udevd/5008: 1, on CPU#1:
#0: ffff88801d69c180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_getlink fs/kernfs/symlink.c:131 [inline]
#0: ffff88801d69c180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_iop_get_link+0xca/0x730 fs/kernfs/symlink.c:151
locks held by kworker/1:0/5690: 5, on CPU#1:
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90003d57c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90003d57c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90003d57c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90003d57c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802b3161d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#2: ffff88802b3161d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff88802b392568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3270 [inline]
#3: ffff88802b392568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5482 [inline]
#3: ffff88802b392568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
#3: ffff88802b392568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
#3: ffff88802b392568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5971
#4: ffff88802b25bd60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5483 [inline]
#4: ffff88802b25bd60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
#4: ffff88802b25bd60 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5889 [inline]
#4: ffff88802b25bd60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5971
locks held by kworker/u8:5/5700: 3, last CPU#1:
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90003d37c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90003d37c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90003d37c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90003d37c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88807f08c258 (&devlink->lock_key#2){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xb30 drivers/net/netdevsim/dev.c:834
locks held by kworker/0:7/5833: 7, on CPU#0:
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff8880206a9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90004bb7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004bb7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004bb7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90004bb7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88802b0b61d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#2: ffff88802b0b61d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff88807f38b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1109 [inline]
#3: ffff88807f38b1d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0 drivers/usb/core/hub.c:2346
#4: ffff88801d69c2a0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3f/0x140 fs/kernfs/dir.c:1790
#5: ffff88801d69c180 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x4e/0x140 fs/kernfs/dir.c:1791
#6: ffffffff9000ec20 (sched_map-wait-type-override){+.+.}-{3:3}, at: sched_submit_work kernel/sched/core.c:7417 [inline]
#6: ffffffff9000ec20 (sched_map-wait-type-override){+.+.}-{3:3}, at: schedule+0x90/0x2b0 kernel/sched/core.c:7473
locks held by udevd/5935: 3, last CPU#1:
#0: ffff888058663580 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1039 [inline]
#0: ffff888058663580 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: lookup_slow+0x46/0x80 fs/namei.c:1935
#1: ffff8880b833c5e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677
#2: ffff8880b8324708 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:928
locks held by udevd/6013: 4, on CPU#0:
#0: ffff888066a6dab8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0 fs/seq_file.c:183
#1: ffff88803348fc80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165
#2: ffff8880758c4008 (kn->active#33){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff8880758c4008 (kn->active#33){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166
#3: ffff88807f38b1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1114 [inline]
#3: ffff88807f38b1d8 (&dev->mutex){....}-{4:4}, at: serial_show+0x26/0xa0 drivers/usb/core/sysfs.c:143
locks held by kworker/u8:24/6082: 3, last CPU#1:
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677
#1: ffff8880b8324708 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:928
#2: ffff8880786d0800 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6990 [inline]
#2: ffff8880786d0800 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0xb4/0x420 net/wireless/core.c:596
locks held by kworker/u8:39/6186: 3, last CPU#1:
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88813fe64148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc9000649fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000649fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000649fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc9000649fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffff88807fd09258 (&devlink->lock_key#9){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xb30 drivers/net/netdevsim/dev.c:834
locks held by udevd/8071: 1, on CPU#1:
#0: ffff8880275b8350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz.5.668/8183: 1, on CPU#1:
#0: ffff8880275b8350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1b8/0x690 block/bdev.c:1173
locks held by syz.3.1170/9971: 1, on CPU#1:
#0: ffff8880275b8350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x276/0x470 block/bdev.c:1369
locks held by getty/10218: 2, on CPU#1:
#0: ffff888033c4e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000357b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.9.1356/10744: 1, on CPU#1:
#0: ffff888036d04260 (&dev->clientlist_mutex){+.+.}-{4:4}, at: drm_client_dev_restore+0xb1/0x290 drivers/gpu/drm/drm_client_event.c:113
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:377 [inline]
watchdog+0x1073/0x10f0 kernel/hung_task.c:598
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:425
Code: e8 5e d8 39 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 7f eb b0 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000aa78b8 EFLAGS: 00000002
RAX: 1ffffffff3853100 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff858f70a0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9c298940 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888123376000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557cbddbc450 CR3: 000000005e7e2000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:134 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:156 [inline]
wait_for_lsr+0x184/0x2f0 drivers/tty/serial/8250/8250_port.c:2036
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3294 [inline]
__serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3369
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3402 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3456 [inline]
serial8250_console_write+0xa7e/0x1200 drivers/tty/serial/8250/8250_port.c:3520
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x6d9/0x8d0 kernel/printk/nbcon.c:1271
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245