syzbot

=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
6.16.0-syzkaller #0 Not tainted
-----------------------------------------------------
kworker/u8:7/3552 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffffffff8ecdf378 (disc_data_lock#2){.+.+}-{3:3}, at: sp_get drivers/net/hamradio/6pack.c:370 [inline]
ffffffff8ecdf378 (disc_data_lock#2){.+.+}-{3:3}, at: sixpack_write_wakeup+0x30/0x480 drivers/net/hamradio/6pack.c:391

and this task is already holding:
ffffffff99dc2bd8 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
ffffffff99dc2bd8 (&port_lock_key){-.-.}-{3:3}, at: uart_port_ref_lock+0xc4/0x3b0 drivers/tty/serial/serial_core.c:83
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+0x120/0x360 kernel/locking/lockdep.c:5871
  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
  _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
  uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
  serial8250_handle_irq+0x6b/0xbb0 drivers/tty/serial/8250/8250_port.c:1917
  serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1966
  serial8250_interrupt+0xa2/0x1d0 drivers/tty/serial/8250/8250_core.c:86
  __handle_irq_event_percpu+0x289/0x980 kernel/irq/handle.c:158
  handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
  handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210
  handle_edge_irq+0x267/0x9c0 kernel/irq/chip.c:797
  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+0x140/0x250 arch/x86/kernel/irq.c:292
  common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:285
  asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
  native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
  pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
  arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
  default_idle+0x13/0x20 arch/x86/kernel/process.c:749
  default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
  cpuidle_idle_call kernel/sched/idle.c:185 [inline]
  do_idle+0x1e8/0x510 kernel/sched/idle.c:325
  cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
  rest_init+0x2de/0x300 init/main.c:745
  start_kernel+0x47d/0x500 init/main.c:1102
  x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
  x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
  common_startup_64+0x13e/0x147

to a HARDIRQ-irq-unsafe lock:
 (disc_data_lock#2){.+.+}-{3:3}

... which became HARDIRQ-irq-unsafe at:
...
  lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
  __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_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676
  tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

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/u8:7/3552:
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000c337bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000c337bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff8880246e8ca0 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x720 drivers/tty/tty_buffer.c:467
 #3: ffff88807a2e90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
 #4: ffffffff99dc2bd8 (&port_lock_key){-.-.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
 #4: ffffffff99dc2bd8 (&port_lock_key){-.-.}-{3:3}, at: uart_port_ref_lock+0xc4/0x3b0 drivers/tty/serial/serial_core.c:83
 #5: ffff88807a2e90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 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+0x120/0x360 kernel/locking/lockdep.c:5871
                    __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                    _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
                    uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
                    serial8250_handle_irq+0x6b/0xbb0 drivers/tty/serial/8250/8250_port.c:1917
                    serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1966
                    serial8250_interrupt+0xa2/0x1d0 drivers/tty/serial/8250/8250_core.c:86
                    __handle_irq_event_percpu+0x289/0x980 kernel/irq/handle.c:158
                    handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
                    handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210
                    handle_edge_irq+0x267/0x9c0 kernel/irq/chip.c:797
                    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+0x140/0x250 arch/x86/kernel/irq.c:292
                    common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:285
                    asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
                    native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
                    pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
                    arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
                    default_idle+0x13/0x20 arch/x86/kernel/process.c:749
                    default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
                    cpuidle_idle_call kernel/sched/idle.c:185 [inline]
                    do_idle+0x1e8/0x510 kernel/sched/idle.c:325
                    cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
                    rest_init+0x2de/0x300 init/main.c:745
                    start_kernel+0x47d/0x500 init/main.c:1102
                    x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
                    x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
                    common_startup_64+0x13e/0x147
   IN-SOFTIRQ-W at:
                    lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
                    __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                    _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
                    uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
                    serial8250_handle_irq+0x6b/0xbb0 drivers/tty/serial/8250/8250_port.c:1917
                    serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1966
                    serial8250_interrupt+0xa2/0x1d0 drivers/tty/serial/8250/8250_core.c:86
                    __handle_irq_event_percpu+0x289/0x980 kernel/irq/handle.c:158
                    handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
                    handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210
                    handle_edge_irq+0x267/0x9c0 kernel/irq/chip.c:797
                    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+0x140/0x250 arch/x86/kernel/irq.c:292
                    common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:285
                    asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
                    check_preemption_disabled+0x17/0x120 lib/smp_processor_id.c:13
                    rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
                    rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:745
                    trace_lock_acquire include/trace/events/lock.h:24 [inline]
                    lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5834
                    rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
                    rcu_read_lock include/linux/rcupdate.h:841 [inline]
                    class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
                    unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
                    arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
                    stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
                    kasan_save_stack mm/kasan/common.c:47 [inline]
                    kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
                    kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
                    poison_slab_object mm/kasan/common.c:247 [inline]
                    __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
                    kasan_slab_free include/linux/kasan.h:233 [inline]
                    slab_free_hook mm/slub.c:2381 [inline]
                    slab_free mm/slub.c:4643 [inline]
                    kfree+0x18e/0x440 mm/slub.c:4842
                    slab_free_after_rcu_debug+0x60/0x2a0 mm/slub.c:4680
                    rcu_do_batch kernel/rcu/tree.c:2576 [inline]
                    rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2832
                    handle_softirqs+0x283/0x870 kernel/softirq.c:579
                    run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968
                    smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164
                    kthread+0x70e/0x8a0 kernel/kthread.c:464
                    ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
                    ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   INITIAL USE at:
                   lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
                   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
                   _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
                   uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
                   serial8250_do_set_termios+0x4bb/0x1c20 drivers/tty/serial/8250/8250_port.c:2774
                   uart_set_options+0x3c2/0x5b0 drivers/tty/serial/serial_core.c:2309
                   serial8250_console_setup+0x2f4/0x3c0 drivers/tty/serial/8250/8250_port.c:3519
                   univ8250_console_setup+0x43a/0x540 drivers/tty/serial/8250/8250_core.c:428
                   console_call_setup kernel/printk/printk.c:3799 [inline]
                   try_enable_preferred_console+0x4e4/0x650 kernel/printk/printk.c:3843
                   register_console+0x551/0xf90 kernel/printk/printk.c:4037
                   univ8250_console_init+0x52/0x90 drivers/tty/serial/8250/8250_core.c:513
                   console_init+0x1a1/0x670 kernel/printk/printk.c:4323
                   start_kernel+0x2cc/0x500 init/main.c:1036
                   x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
                   x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
                   common_startup_64+0x13e/0x147
 }
 ... key      at: [<ffffffff99dc1fa0>] 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+0x120/0x360 kernel/locking/lockdep.c:5871
                    __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_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676
                    tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
                    vfs_ioctl fs/ioctl.c:51 [inline]
                    __do_sys_ioctl fs/ioctl.c:907 [inline]
                    __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
                    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                    do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
                    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   SOFTIRQ-ON-R at:
                    lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
                    __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_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676
                    tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
                    vfs_ioctl fs/ioctl.c:51 [inline]
                    __do_sys_ioctl fs/ioctl.c:907 [inline]
                    __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
                    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                    do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
                    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL USE at:
                   lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
                   __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline]
                   _raw_write_lock_irq+0xa2/0xf0 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+0x174/0x200 drivers/tty/tty_ldisc.c:781
                   tty_release_struct+0x2a/0xd0 drivers/tty/tty_io.c:1681
                   tty_release+0xcb0/0x1640 drivers/tty/tty_io.c:1852
                   __fput+0x449/0xa70 fs/file_table.c:465
                   task_work_run+0x1d1/0x260 kernel/task_work.c:227
                   resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
                   exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
                   exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
                   syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
                   syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
                   do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
                   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   INITIAL READ USE at:
                        lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
                        __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_ioctl+0x84/0x590 drivers/net/hamradio/6pack.c:676
                        tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
                        vfs_ioctl fs/ioctl.c:51 [inline]
                        __do_sys_ioctl fs/ioctl.c:907 [inline]
                        __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
                        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
                        do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
                        entry_SYSCALL_64_after_hwframe+0x77/0x7f
 }
 ... key      at: [<ffffffff8ecdf378>] disc_data_lock+0x18/0x100 6pack.c:-1
 ... acquired at:
   lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
   __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+0x30/0x480 drivers/net/hamradio/6pack.c:391
   tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:515
   tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
   serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1838
   __start_tx+0x33b/0x480 drivers/tty/serial/8250/8250_port.c:1543
   __uart_start+0x23f/0x440 drivers/tty/serial/serial_core.c:161
   uart_write+0xdc/0x130 drivers/tty/serial/serial_core.c:636
   decode_prio_command drivers/net/hamradio/6pack.c:868 [inline]
   sixpack_decode drivers/net/hamradio/6pack.c:943 [inline]
   sixpack_receive_buf+0x447/0x1450 drivers/net/hamradio/6pack.c:447
   tty_ldisc_receive_buf+0x116/0x160 drivers/tty/tty_buffer.c:391
   tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
   receive_buf drivers/tty/tty_buffer.c:445 [inline]
   flush_to_ldisc+0x24a/0x720 drivers/tty/tty_buffer.c:495
   process_one_work kernel/workqueue.c:3238 [inline]
   process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
   worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
   kthread+0x70e/0x8a0 kernel/kthread.c:464
   ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245


stack backtrace:
CPU: 1 UID: 0 PID: 3552 Comm: kworker/u8:7 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_bad_irq_dependency kernel/locking/lockdep.c:2619 [inline]
 check_irq_usage kernel/locking/lockdep.c:2860 [inline]
 check_prev_add kernel/locking/lockdep.c:3172 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0x1f05/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 __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+0x30/0x480 drivers/net/hamradio/6pack.c:391
 tty_wakeup+0xbb/0x100 drivers/tty/tty_io.c:515
 tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
 serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1838
 __start_tx+0x33b/0x480 drivers/tty/serial/8250/8250_port.c:1543
 __uart_start+0x23f/0x440 drivers/tty/serial/serial_core.c:161
 uart_write+0xdc/0x130 drivers/tty/serial/serial_core.c:636
 decode_prio_command drivers/net/hamradio/6pack.c:868 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:943 [inline]
 sixpack_receive_buf+0x447/0x1450 drivers/net/hamradio/6pack.c:447
 tty_ldisc_receive_buf+0x116/0x160 drivers/tty/tty_buffer.c:391
 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x24a/0x720 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>