INFO: task getty:4028 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:21744 pid:4028  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
 __flush_work+0x938/0xac0 kernel/workqueue.c:3076
 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3163
 hci_unregister_dev+0x17c/0x500 net/bluetooth/hci_core.c:2710
 hci_uart_tty_close+0x268/0x330 drivers/bluetooth/hci_ldisc.c:578
 tty_ldisc_reinit+0xe4/0x460 drivers/tty/tty_ldisc.c:661
 tty_ldisc_hangup+0x360/0x4a0 drivers/tty/tty_ldisc.c:726
 __tty_hangup+0x40e/0x660 drivers/tty/tty_io.c:631
 disassociate_ctty+0x38b/0x850 drivers/tty/tty_jobctrl.c:275
 do_exit+0x999/0x2570 kernel/exit.c:885
 do_group_exit+0x229/0x2e0 kernel/exit.c:1030
 __do_sys_exit_group kernel/exit.c:1041 [inline]
 __se_sys_exit_group kernel/exit.c:1039 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1039
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff23dee06c5
RSP: 002b:00007fff527afea8 EFLAGS: 00000206
 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ff23dfe1fe8 RCX: 00007ff23dee06c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 0000000000000001 R08: 00007fff527afe38 R09: 0000000000000000
R10: 00007fff527afcd0 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ff23dfe0680 R15: 00007ff23dfe2000
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e5b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2edd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
3 locks held by kworker/u5:0/49:
 #0: ffff88807479f938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000ba7d00 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff888072f991e0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open net/bluetooth/hci_core.c:450 [inline]
 #2: ffff888072f991e0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_power_on+0x19f/0x6b0 net/bluetooth/hci_core.c:953
2 locks held by getty/4028:
 #0: ffff88814d4971c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: __tty_hangup+0xbb/0x660 drivers/tty/tty_io.c:591
 #1: ffff88814d497098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:290 [inline]
 #1: ffff88814d497098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x68/0xb0 drivers/tty/tty_ldisc.c:314
2 locks held by kworker/1:7/4401:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900049f7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
1 lock held by syz-executor/5211:
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz-executor/5697:
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by rm/6932:

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:mark_usage kernel/locking/lockdep.c:4513 [inline]
RIP: 0010:__lock_acquire+0xc09/0x7c40 kernel/locking/lockdep.c:5017
Code: 30 bd 0c 00 0f 84 8e 0f 00 00 83 bc 24 a8 00 00 00 00 4c 8b b4 24 a0 00 00 00 0f 84 e3 01 00 00 48 8b 44 24 40 42 0f b6 04 00 <84> c0 0f 85 24 5c 00 00 41 8b 07 66 85 c0 48 8b 5c 24 20 0f 88 d0
RSP: 0018:ffffc900001077a0 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff8164182e
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90b13318
RBP: ffffc900001079d0 R08: dffffc0000000000 R09: 1ffffffff2162663
R10: dffffc0000000000 R11: fffffbfff2162664 R12: ffff88813fec46d8
R13: ffff88813fec4750 R14: ffff88813fec4730 R15: ffff88813fec4750
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564f32f35168 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x32/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:356 [inline]
 batadv_nc_purge_paths+0xe2/0x3a0 net/batman-adv/network-coding.c:442
 batadv_nc_worker+0x35f/0x600 net/batman-adv/network-coding.c:722
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>