INFO: task kworker/0:1:10 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1 state:D stack:22008 pid:10 tgid:10 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: events console_callback
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:293 [inline]
__down_common+0x371/0x8b0 kernel/locking/semaphore.c:318
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2896
class_console_lock_constructor include/linux/console.h:734 [inline]
console_callback+0x62/0x4c0 drivers/tty/vt/vt.c:3352
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task kworker/u8:33:21033 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:33 state:D stack:24328 pid:21033 tgid:21033 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821
class_mutex_constructor include/linux/mutex.h:253 [inline]
commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:736
n_tty_receive_char+0x3f5/0x600 drivers/tty/n_tty.c:1413
n_tty_receive_buf_standard+0x6b2/0x3090 drivers/tty/n_tty.c:1582
__receive_buf drivers/tty/n_tty.c:1616 [inline]
n_tty_receive_buf_common+0x349/0x1930 drivers/tty/n_tty.c:1715
tty_ldisc_receive_buf+0xaa/0x1a0 drivers/tty/tty_buffer.c:394
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:452 [inline]
flush_to_ldisc+0x26b/0x730 drivers/tty/tty_buffer.c:502
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INFO: task syz.6.5170:27334 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.6.5170 state:D stack:27592 pid:27334 tgid:27333 ppid:26481 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:293 [inline]
__down_common+0x371/0x8b0 kernel/locking/semaphore.c:318
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2896
class_console_lock_constructor include/linux/console.h:734 [inline]
vcs_open+0x64/0xc0 drivers/tty/vt/vc_screen.c:746
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4863
do_file_open+0x20e/0x430 fs/namei.c:4892
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f024d95e6ce
RSP: 002b:00007f024e883b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f024e8846c0 RCX: 00007f024d95e6ce
RDX: 0000000000004004 RSI: 00007f024e883c00 RDI: ffffffffffffff9c
RBP: 00007f024e883c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f024dc26038 R14: 00007f024dc25fa0 R15: 00007ffcca58ab98
INFO: task syz.3.5173:27384 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.3.5173 state:D stack:26744 pid:27384 tgid:27383 ppid:26991 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:293 [inline]
__down_common+0x371/0x8b0 kernel/locking/semaphore.c:318
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2896
class_console_lock_constructor include/linux/console.h:734 [inline]
vcs_open+0x64/0xc0 drivers/tty/vt/vc_screen.c:746
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4863
do_file_open+0x20e/0x430 fs/namei.c:4892
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5fd9f9de99
RSP: 002b:00007f5fdaefc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5fda225fa0 RCX: 00007f5fd9f9de99
RDX: 0000000000040102 RSI: 00002000000000c0 RDI: ffffffffffffff9c
RBP: 00007f5fda033eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5fda226038 R14: 00007f5fda225fa0 R15: 00007ffd193c06c8
Showing all locks held in the system:
2 locks held by kworker/0:1/10:
#0: ffff88801bc0f140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc900000f7d08 (console_work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
1 lock held by rcu_tasks_kthre/28:
#0: ffffffff8ebe7908 (rcu_tasks.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0x61f/0xd90 kernel/rcu/tasks.h:611
1 lock held by khungtaskd/31:
#0: ffffffff8ebe8180 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe8180 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe8180 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
1 lock held by udevd/4975:
2 locks held by getty/5363:
#0: ffff888033edd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
6 locks held by kworker/u8:33/21033:
#0: ffff88801bc44140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000348fd08 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88801bc620b8 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x34/0x730 drivers/tty/tty_buffer.c:474
#3: ffff8880789580a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x21/0x90 drivers/tty/tty_ldisc.c:263
#4: ffff8880789582c8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_read_constructor include/linux/rwsem.h:259 [inline]
#4: ffff8880789582c8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_receive_buf_common+0x85/0x1930 drivers/tty/n_tty.c:1678
#5: ffffc900026ba370 (&ldata->output_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#5: ffffc900026ba370 (&ldata->output_lock){+.+.}-{4:4}, at: commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:736
6 locks held by syz.0.5057/26779:
1 lock held by udevd/29382:
2 locks held by syz.7.5474/29946:
2 locks held by syz.3.5478/29969:
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x539/0xfa0 drivers/tty/tty_io.c:2120
#1: ffff88807cedc1b0 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_init_dev.part.0+0x39/0x470 drivers/tty/tty_io.c:1406
4 locks held by syz-executor/30019:
1 lock held by syz.7.5515/30242:
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x539/0xfa0 drivers/tty/tty_io.c:2120
4 locks held by syz-executor/30292:
1 lock held by syz.1.5524/30407:
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open_by_driver drivers/tty/tty_io.c:2037 [inline]
#0: ffffffff8f986b20 (tty_mutex){+.+.}-{4:4}, at: tty_open+0x539/0xfa0 drivers/tty/tty_io.c:2120
3 locks held by rm/30559:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245