syzbot

=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
6.12.0-syzkaller-01518-ga5c93bfec0be #0 Not tainted
-----------------------------------------------------
kworker/u8:27/7638 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8f3353b8 (disc_data_lock#4){.+.+}-{3:3}, at: sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370

and this task is already holding:
ffffffff9ab02e98 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
ffffffff9ab02e98 (&port_lock_key){-.-.}-{3:3}, at: uart_write+0x13b/0xb30 drivers/tty/serial/serial_core.c:626
which would create a new lock dependency:
 (&port_lock_key){-.-.}-{3:3} -> (disc_data_lock#4){.+.+}-{3:3}

but this new dependency connects a HARDIRQ-irq-safe lock:
 (&port_lock_key){-.-.}-{3:3}

... which became HARDIRQ-irq-safe at:
  lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
  uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
  serial8250_handle_irq+0x95/0xc80 drivers/tty/serial/8250/8250_port.c:1900
  serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949
  serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86
  __handle_irq_event_percpu+0x229/0x7c0 kernel/irq/handle.c:158
  handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
  handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
  handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831
  generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
  handle_irq arch/x86/kernel/irq.c:247 [inline]
  call_irq_handler arch/x86/kernel/irq.c:259 [inline]
  __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285
  common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:278
  asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
  __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
  _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
  spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
  uart_port_unlock_irqrestore include/linux/serial_core.h:782 [inline]
  uart_write+0x2a4/0xb30 drivers/tty/serial/serial_core.c:636
  process_output_block drivers/tty/n_tty.c:574 [inline]
  n_tty_write+0x419/0x1140 drivers/tty/n_tty.c:2389
  iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
  file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
  tty_write drivers/tty/tty_io.c:1111 [inline]
  redirected_tty_write drivers/tty/tty_io.c:1134 [inline]
  redirected_tty_write+0xcc/0x140 drivers/tty/tty_io.c:1114
  new_sync_write fs/read_write.c:586 [inline]
  vfs_write+0x5ae/0x1150 fs/read_write.c:679
  ksys_write+0x12b/0x250 fs/read_write.c:731
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

to a HARDIRQ-irq-unsafe lock:
 (disc_data_lock#4){.+.+}-{3:3}

... which became HARDIRQ-irq-unsafe at:
...
  lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
  __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
  _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
  sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
  sixpack_receive_buf drivers/net/hamradio/6pack.c:433 [inline]
  sixpack_receive_buf+0x59/0x1c50 drivers/net/hamradio/6pack.c:424
  tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
  tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
  receive_buf drivers/tty/tty_buffer.c:445 [inline]
  flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
  process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
  process_scheduled_works kernel/workqueue.c:3310 [inline]
  worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
  kthread+0x2c1/0x3a0 kernel/kthread.c:389
  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(disc_data_lock#4);
                               local_irq_disable();
                               lock(&port_lock_key);
                               lock(disc_data_lock#4);
  <Interrupt>
    lock(&port_lock_key);

 *** DEADLOCK ***

6 locks held by kworker/u8:27/7638:
 #0: ffff88801b081148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x129b/0x1ba0 kernel/workqueue.c:3204
 #1: ffffc900037bfd80 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205
 #2: ffff888024fd8ca0 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x31/0x780 drivers/tty/tty_buffer.c:467
 #3: ffff88807b5420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263
 #4: ffffffff9ab02e98 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
 #4: ffffffff9ab02e98 (&port_lock_key){-.-.}-{3:3}, at: uart_write+0x13b/0xb30 drivers/tty/serial/serial_core.c:626
 #5: ffff88807b5420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263

the dependencies between HARDIRQ-irq-safe lock and the holding lock:
-> (&port_lock_key){-.-.}-{3:3} {
   IN-HARDIRQ-W at:
                    lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                    __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                    _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
                    uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
                    serial8250_handle_irq+0x95/0xc80 drivers/tty/serial/8250/8250_port.c:1900
                    serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949
                    serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86
                    __handle_irq_event_percpu+0x229/0x7c0 kernel/irq/handle.c:158
                    handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
                    handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
                    handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831
                    generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
                    handle_irq arch/x86/kernel/irq.c:247 [inline]
                    call_irq_handler arch/x86/kernel/irq.c:259 [inline]
                    __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285
                    common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:278
                    asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
                    __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
                    _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
                    spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
                    uart_port_unlock_irqrestore include/linux/serial_core.h:782 [inline]
                    uart_write+0x2a4/0xb30 drivers/tty/serial/serial_core.c:636
                    process_output_block drivers/tty/n_tty.c:574 [inline]
                    n_tty_write+0x419/0x1140 drivers/tty/n_tty.c:2389
                    iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
                    file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
                    tty_write drivers/tty/tty_io.c:1111 [inline]
                    redirected_tty_write drivers/tty/tty_io.c:1134 [inline]
                    redirected_tty_write+0xcc/0x140 drivers/tty/tty_io.c:1114
                    new_sync_write fs/read_write.c:586 [inline]
                    vfs_write+0x5ae/0x1150 fs/read_write.c:679
                    ksys_write+0x12b/0x250 fs/read_write.c:731
                    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
                    do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
                    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   IN-SOFTIRQ-W at:
                    lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                    __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                    _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
                    uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
                    serial8250_handle_irq+0x95/0xc80 drivers/tty/serial/8250/8250_port.c:1900
                    serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949
                    serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86
                    __handle_irq_event_percpu+0x229/0x7c0 kernel/irq/handle.c:158
                    handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
                    handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
                    handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831
                    generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
                    handle_irq arch/x86/kernel/irq.c:247 [inline]
                    call_irq_handler arch/x86/kernel/irq.c:259 [inline]
                    __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285
                    common_interrupt+0x61/0xe0 arch/x86/kernel/irq.c:278
                    asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
                    raw_spin_rq_unlock_irqrestore kernel/sched/sched.h:1542 [inline]
                    rq_unlock_irqrestore kernel/sched/sched.h:1821 [inline]
                    sched_balance_update_blocked_averages+0x10aa/0x1cb0 kernel/sched/fair.c:9864
                    sched_balance_softirq+0x122/0x1a0 kernel/sched/fair.c:12866
                    handle_softirqs+0x213/0x8f0 kernel/softirq.c:554
                    __do_softirq kernel/softirq.c:588 [inline]
                    invoke_softirq kernel/softirq.c:428 [inline]
                    __irq_exit_rcu kernel/softirq.c:637 [inline]
                    irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649
                    instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
                    sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049
                    asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
                    console_flush_all+0x9a4/0xc60 kernel/printk/printk.c:3182
                    __console_flush_and_unlock kernel/printk/printk.c:3240 [inline]
                    console_unlock+0xd9/0x210 kernel/printk/printk.c:3280
                    vprintk_emit+0x424/0x6f0 kernel/printk/printk.c:2408
                    vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:68
                    _printk+0xc8/0x100 kernel/printk/printk.c:2433
                    kauditd_printk_skb kernel/audit.c:546 [inline]
                    kauditd_hold_skb+0x205/0x250 kernel/audit.c:581
                    kauditd_send_queue+0x236/0x290 kernel/audit.c:766
                    kauditd_thread+0x611/0xa60 kernel/audit.c:890
                    kthread+0x2c1/0x3a0 kernel/kthread.c:389
                    ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
   INITIAL USE at:
                   lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                   _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
                   uart_port_lock_irqsave include/linux/serial_core.h:711 [inline]
                   serial8250_do_set_termios+0x307/0x16f0 drivers/tty/serial/8250/8250_port.c:2742
                   serial8250_set_termios+0x6e/0x80 drivers/tty/serial/8250/8250_port.c:2861
                   uart_set_options+0x31b/0x5f0 drivers/tty/serial/serial_core.c:2327
                   serial8250_console_setup+0x18a/0x460 drivers/tty/serial/8250/8250_port.c:3456
                   univ8250_console_setup+0x1d4/0x2c0 drivers/tty/serial/8250/8250_core.c:428
                   console_call_setup kernel/printk/printk.c:3744 [inline]
                   console_call_setup kernel/printk/printk.c:3735 [inline]
                   try_enable_preferred_console+0x2fd/0x530 kernel/printk/printk.c:3788
                   register_console+0x3ac/0x1170 kernel/printk/printk.c:3982
                   univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:513
                   console_init+0xcc/0x680 kernel/printk/printk.c:4263
                   start_kernel+0x29a/0x4d0 init/main.c:1040
                   x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
                   x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
                   common_startup_64+0x13e/0x148
 }
 ... key      at: [<ffffffff9ab02100>] port_lock_key+0x0/0x40

the dependencies between the lock to be acquired
 and HARDIRQ-irq-unsafe lock:
-> (disc_data_lock#4){.+.+}-{3:3} {
   HARDIRQ-ON-R at:
                    lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                    __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                    _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
                    sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
                    sixpack_receive_buf drivers/net/hamradio/6pack.c:433 [inline]
                    sixpack_receive_buf+0x59/0x1c50 drivers/net/hamradio/6pack.c:424
                    tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
                    tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
                    receive_buf drivers/tty/tty_buffer.c:445 [inline]
                    flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
                    process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
                    process_scheduled_works kernel/workqueue.c:3310 [inline]
                    worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
                    kthread+0x2c1/0x3a0 kernel/kthread.c:389
                    ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
   SOFTIRQ-ON-R at:
                    lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                    __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                    _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
                    sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
                    sixpack_receive_buf drivers/net/hamradio/6pack.c:433 [inline]
                    sixpack_receive_buf+0x59/0x1c50 drivers/net/hamradio/6pack.c:424
                    tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
                    tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
                    receive_buf drivers/tty/tty_buffer.c:445 [inline]
                    flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
                    process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
                    process_scheduled_works kernel/workqueue.c:3310 [inline]
                    worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
                    kthread+0x2c1/0x3a0 kernel/kthread.c:389
                    ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
   INITIAL READ USE at:
                        lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
                        __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
                        _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
                        sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
                        sixpack_receive_buf drivers/net/hamradio/6pack.c:433 [inline]
                        sixpack_receive_buf+0x59/0x1c50 drivers/net/hamradio/6pack.c:424
                        tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
                        tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
                        receive_buf drivers/tty/tty_buffer.c:445 [inline]
                        flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
                        process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
                        process_scheduled_works kernel/workqueue.c:3310 [inline]
                        worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
                        kthread+0x2c1/0x3a0 kernel/kthread.c:389
                        ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
                        ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 }
 ... key      at: [<ffffffff8f3353b8>] disc_data_lock+0x18/0xfa0
 ... acquired at:
   lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
   __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
   _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
   sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
   sixpack_write_wakeup+0x20/0x390 drivers/net/hamradio/6pack.c:391
   tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:517
   tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
   serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1821
   __start_tx+0x3e9/0x4a0 drivers/tty/serial/8250/8250_port.c:1527
   serial8250_start_tx+0x363/0x530 drivers/tty/serial/8250/8250_port.c:1636
   __uart_start+0x292/0x4c0 drivers/tty/serial/serial_core.c:160
   uart_write+0x218/0xb30 drivers/tty/serial/serial_core.c:635
   decode_prio_command drivers/net/hamradio/6pack.c:868 [inline]
   sixpack_decode drivers/net/hamradio/6pack.c:943 [inline]
   sixpack_receive_buf drivers/net/hamradio/6pack.c:447 [inline]
   sixpack_receive_buf+0x3d7/0x1c50 drivers/net/hamradio/6pack.c:424
   tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
   tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
   receive_buf drivers/tty/tty_buffer.c:445 [inline]
   flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
   process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
   process_scheduled_works kernel/workqueue.c:3310 [inline]
   worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
   kthread+0x2c1/0x3a0 kernel/kthread.c:389
   ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244


stack backtrace:
CPU: 1 UID: 0 PID: 7638 Comm: kworker/u8:27 Not tainted 6.12.0-syzkaller-01518-ga5c93bfec0be #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_bad_irq_dependency kernel/locking/lockdep.c:2647 [inline]
 check_irq_usage+0xf22/0x1290 kernel/locking/lockdep.c:2888
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain kernel/locking/lockdep.c:3904 [inline]
 __lock_acquire+0x24b4/0x3c40 kernel/locking/lockdep.c:5226
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
 _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228
 sp_get+0x18/0xf0 drivers/net/hamradio/6pack.c:370
 sixpack_write_wakeup+0x20/0x390 drivers/net/hamradio/6pack.c:391
 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:517
 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
 serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1821
 __start_tx+0x3e9/0x4a0 drivers/tty/serial/8250/8250_port.c:1527
 serial8250_start_tx+0x363/0x530 drivers/tty/serial/8250/8250_port.c:1636
 __uart_start+0x292/0x4c0 drivers/tty/serial/serial_core.c:160
 uart_write+0x218/0xb30 drivers/tty/serial/serial_core.c:635
 decode_prio_command drivers/net/hamradio/6pack.c:868 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:943 [inline]
 sixpack_receive_buf drivers/net/hamradio/6pack.c:447 [inline]
 sixpack_receive_buf+0x3d7/0x1c50 drivers/net/hamradio/6pack.c:424
 tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
 tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>