=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 Not tainted
-----------------------------------------------------
kworker/u8:17/28538 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8f8ccaf8 (disc_data_lock#2){.+.+}-{3:3}, at: sp_get drivers/net/hamradio/6pack.c:370 [inline]
ffffffff8f8ccaf8 (disc_data_lock#2){.+.+}-{3:3}, at: sixpack_write_wakeup+0x30/0x440 drivers/net/hamradio/6pack.c:391
and this task is already holding:
ffffffff9aa48458 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
ffffffff9aa48458 (&port_lock_key){-.-.}-{3:3}, at: uart_write+0x107/0xa40 drivers/tty/serial/serial_core.c:626
which would create a new lock dependency:
(&port_lock_key){-.-.}-{3:3} -> (disc_data_lock#2){.+.+}-{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+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
serial8250_handle_irq+0x6d/0xb80 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:86
__handle_irq_event_percpu+0x29c/0xa60 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210
handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:266 [inline]
__common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:292
common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:285
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xd9/0x140 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:786 [inline]
uart_write+0x3e4/0xa40 drivers/tty/serial/serial_core.c:636
process_output_block drivers/tty/n_tty.c:561 [inline]
n_tty_write+0xd81/0x1270 drivers/tty/n_tty.c:2377
iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
file_tty_write+0x543/0x9d0 drivers/tty/tty_io.c:1090
new_sync_write fs/read_write.c:591 [inline]
vfs_write+0x70f/0xd10 fs/read_write.c:684
ksys_write+0x19d/0x2d0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
to a HARDIRQ-irq-unsafe lock:
(disc_data_lock#2){.+.+}-{3:3}
... which became HARDIRQ-irq-unsafe at:
...
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_receive_buf+0x57/0x1420 drivers/net/hamradio/6pack.c:433
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(disc_data_lock#2);
local_irq_disable();
lock(&port_lock_key);
lock(disc_data_lock#2);
<Interrupt>
lock(&port_lock_key);
*** DEADLOCK ***
6 locks held by kworker/u8:17/28538:
#0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
#1: ffffc9000b587c60 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc9000b587c60 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
#2: ffff888025320ca0 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x860 drivers/tty/tty_buffer.c:467
#3: ffff8880251ec0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263
#4: ffffffff9aa48458 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
#4: ffffffff9aa48458 (&port_lock_key){-.-.}-{3:3}, at: uart_write+0x107/0xa40 drivers/tty/serial/serial_core.c:626
#5: ffff8880251ec0a0 (&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+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
serial8250_handle_irq+0x6d/0xb80 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:86
__handle_irq_event_percpu+0x29c/0xa60 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210
handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:266 [inline]
__common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:292
common_interrupt+0xb4/0xd0 arch/x86/kernel/irq.c:285
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0xd9/0x140 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:786 [inline]
uart_write+0x3e4/0xa40 drivers/tty/serial/serial_core.c:636
process_output_block drivers/tty/n_tty.c:561 [inline]
n_tty_write+0xd81/0x1270 drivers/tty/n_tty.c:2377
iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
file_tty_write+0x543/0x9d0 drivers/tty/tty_io.c:1090
new_sync_write fs/read_write.c:591 [inline]
vfs_write+0x70f/0xd10 fs/read_write.c:684
ksys_write+0x19d/0x2d0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
IN-SOFTIRQ-W at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
serial8250_handle_irq+0x6d/0xb80 drivers/tty/serial/8250/8250_port.c:1921
serial8250_default_handle_irq+0xd1/0x1f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_interrupt+0xa9/0x1f0 drivers/tty/serial/8250/8250_core.c:86
__handle_irq_event_percpu+0x29c/0xa60 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210
handle_edge_irq+0x25f/0xc20 kernel/irq/chip.c:831
generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
handle_irq arch/x86/kernel/irq.c:254 [inline]
call_irq_handler arch/x86/kernel/irq.c:266 [inline]
__common_interrupt+0x136/0x230 arch/x86/kernel/irq.c:292
common_interrupt+0x5e/0xd0 arch/x86/kernel/irq.c:285
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
rcu_is_watching+0x44/0xb0 kernel/rcu/tree.c:736
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x4e/0x3e0 kernel/locking/lockdep.c:5877
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
__free_frozen_pages+0x810/0x10a0 mm/page_alloc.c:2754
pagetable_free include/linux/mm.h:3002 [inline]
pagetable_dtor_free include/linux/mm.h:3100 [inline]
__tlb_remove_table+0x36b/0x460 include/asm-generic/tlb.h:215
__tlb_remove_table_free mm/mmu_gather.c:227 [inline]
tlb_remove_table_rcu+0x79/0xf0 mm/mmu_gather.c:290
rcu_do_batch kernel/rcu/tree.c:2568 [inline]
rcu_core+0xaac/0x17a0 kernel/rcu/tree.c:2824
handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xfb/0x220 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:80
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:748
default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:185 [inline]
do_idle+0x22e/0x5d0 kernel/sched/idle.c:325
cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
rest_init+0x2dc/0x300 init/main.c:743
start_kernel+0x484/0x510 init/main.c:1099
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
common_startup_64+0x13e/0x147
INITIAL USE at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
serial8250_do_set_termios+0x4dc/0x1c70 drivers/tty/serial/8250/8250_port.c:2778
uart_set_options+0x439/0x780 drivers/tty/serial/serial_core.c:2310
serial8250_console_setup+0x3dd/0x670 drivers/tty/serial/8250/8250_port.c:3519
univ8250_console_setup+0x429/0x530 drivers/tty/serial/8250/8250_core.c:428
console_call_setup kernel/printk/printk.c:3799 [inline]
try_enable_preferred_console+0x46b/0x5c0 kernel/printk/printk.c:3843
register_console+0x37d/0x1080 kernel/printk/printk.c:4037
univ8250_console_init+0x52/0x90 drivers/tty/serial/8250/8250_core.c:513
console_init+0x1b8/0x6f0 kernel/printk/printk.c:4323
start_kernel+0x2dd/0x510 init/main.c:1034
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
common_startup_64+0x13e/0x147
}
... key at: [<ffffffff9aa47820>] port_lock_key+0x0/0x20
the dependencies between the lock to be acquired
and HARDIRQ-irq-unsafe lock:
-> (disc_data_lock#2){.+.+}-{3:3} {
HARDIRQ-ON-R at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_receive_buf+0x57/0x1420 drivers/net/hamradio/6pack.c:433
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
SOFTIRQ-ON-R at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_receive_buf+0x57/0x1420 drivers/net/hamradio/6pack.c:433
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
INITIAL USE at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
_raw_write_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:326
sixpack_close+0x2c/0x280 drivers/net/hamradio/6pack.c:641
tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613
tty_ldisc_release+0x1a1/0x200 drivers/tty/tty_ldisc.c:781
tty_release_struct+0x2b/0xe0 drivers/tty/tty_io.c:1690
tty_release+0xd07/0x12c0 drivers/tty/tty_io.c:1861
__fput+0x3e9/0x9f0 fs/file_table.c:465
task_work_run+0x251/0x310 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
do_syscall_64+0x100/0x210 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
INITIAL READ USE at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_receive_buf+0x57/0x1420 drivers/net/hamradio/6pack.c:433
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
}
... key at: [<ffffffff8f8ccaf8>] disc_data_lock+0x18/0x100 6pack.c:-1
... acquired at:
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_write_wakeup+0x30/0x440 drivers/net/hamradio/6pack.c:391
tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:517
tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69
serial8250_tx_chars+0x6e2/0x930 drivers/tty/serial/8250/8250_port.c:1842
__start_tx+0x32e/0x470 drivers/tty/serial/8250/8250_port.c:1547
__uart_start+0x2bc/0x450 drivers/tty/serial/serial_core.c:160
uart_write+0x280/0xa40 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+0x447/0x1420 drivers/net/hamradio/6pack.c:447
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
stack backtrace:
CPU: 0 UID: 0 PID: 28538 Comm: kworker/u8:17 Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_bad_irq_dependency kernel/locking/lockdep.c:2652 [inline]
check_irq_usage kernel/locking/lockdep.c:2893 [inline]
check_prev_add kernel/locking/lockdep.c:3170 [inline]
check_prevs_add kernel/locking/lockdep.c:3285 [inline]
validate_chain+0x22bb/0x24e0 kernel/locking/lockdep.c:3909
__lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
__raw_read_lock include/linux/rwlock_api_smp.h:150 [inline]
_raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:228
sp_get drivers/net/hamradio/6pack.c:370 [inline]
sixpack_write_wakeup+0x30/0x440 drivers/net/hamradio/6pack.c:391
tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:517
tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69
serial8250_tx_chars+0x6e2/0x930 drivers/tty/serial/8250/8250_port.c:1842
__start_tx+0x32e/0x470 drivers/tty/serial/8250/8250_port.c:1547
__uart_start+0x2bc/0x450 drivers/tty/serial/serial_core.c:160
uart_write+0x280/0xa40 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+0x447/0x1420 drivers/net/hamradio/6pack.c:447
tty_ldisc_receive_buf+0x11f/0x170 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x32b/0x860 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>