INFO: task getty:3942 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:getty           state:D
 stack:22288 pid: 3942 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __flush_work+0x15a/0x210 kernel/workqueue.c:3094
 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181
 hci_unregister_dev+0x163/0x590 net/bluetooth/hci_core.c:4061
 hci_uart_tty_close+0x268/0x330 drivers/bluetooth/hci_ldisc.c:575
 tty_ldisc_reinit+0xe4/0x460 drivers/tty/tty_ldisc.c:679
 tty_ldisc_hangup+0x360/0x4a0 drivers/tty/tty_ldisc.c:745
 __tty_hangup+0x44e/0x670 drivers/tty/tty_io.c:639
 disassociate_ctty+0x38d/0x860 drivers/tty/tty_jobctrl.c:275
 do_exit+0x5f9/0x2110 kernel/exit.c:888
 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb83648f6c5
RSP: 002b:00007fff80b409a8 EFLAGS: 00000206
 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fb836590fe8 RCX: 00007fb83648f6c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 0000000000000001 R08: 00007fff80b40938 R09: 0000000000000000
R10: 00007fff80b407d0 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fb83658f680 R15: 00007fb836591000
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/1:3/1322:
 #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc900055d7d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
2 locks held by getty/3942:
 #0: ffff88814cb781c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: __tty_hangup+0xc0/0x670 drivers/tty/tty_io.c:599
 #1: ffff88814cb78098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:300 [inline]
 #1: ffff88814cb78098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x68/0xb0 drivers/tty/tty_ldisc.c:324
2 locks held by syz-executor/4184:
 #0: ffff8880205f5918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf1/0x780 block/bdev.c:911
 #1: ffff88802067e468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa9/0xb50 drivers/block/loop.c:1366
4 locks held by kworker/u5:3/4195:
 #0: ffff8880237b4938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90002f3fd00 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88807b8c53f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xa4/0x12a0 net/bluetooth/hci_core.c:1464
 #3: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x98/0x130 kernel/sched/core.c:483
2 locks held by kworker/u4:9/4675:
 #0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x98/0x130 kernel/sched/core.c:483
 #1: ffff8880b9127888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x4c3/0x810 kernel/sched/psi.c:882
7 locks held by syz.1.206/5078:
 #0: ffff88807f6059f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff8880782e0460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffff88805fcba888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1dc/0x500 fs/kernfs/file.c:287
 #3: ffff88801bf23178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:809 [inline]
 #3: ffff88801bf23178 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1064 [inline]
 #3: ffff88801bf23178 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa1/0x710 drivers/base/dd.c:1279
 #4: ffffffff8ca0bee8 (serial_mutex){+.+.}-{3:3}, at: serial8250_unregister_port+0x49/0x240 drivers/tty/serial/8250/8250_core.c:1143
 #5: ffffffff8ca091c8 (port_mutex){+.+.}-{3:3}, at: uart_remove_one_port+0xda/0x820 drivers/tty/serial/serial_core.c:3042
 #6: ffff88814cb781c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: __tty_hangup+0xc0/0x670 drivers/tty/tty_io.c:599
2 locks held by dhcpcd/6662:
 #0: ffff88805c516e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff88805c516e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff88805c516e10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/6664:
 #0: ffff88805c512010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff88805c512010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff88805c512010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
1 lock held by dhcpcd/6665:
 #0: ffff88805c51dc10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff88805c51dc10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff88805c51dc10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
1 lock held by dhcpcd/6666:
 #0: ffff88805c51d010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff88805c51d010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff88805c51d010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
2 locks held by dhcpcd/6667:
 #0: ffff8880604bb210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #0: ffff8880604bb210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
 #0: ffff8880604bb210 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x82/0x210 net/socket.c:1346
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729