FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.16.0-syzkaller-11105-ga6923c06a3b2 #0 Not tainted
------------------------------------------------------
syz.1.355/7542 is trying to acquire lock:
ffffffff8e12e0a0 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
ffffffff8e12e0a0 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
ffffffff8e12e0a0 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
ffffffff8e12e0a0 (console_owner){-...}-{0:0}, at: console_flush_all+0x13a/0xc40 kernel/printk/printk.c:3203

but task is already holding lock:
ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&rq->__lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
       raw_spin_rq_lock kernel/sched/sched.h:1519 [inline]
       task_rq_lock+0xbc/0x470 kernel/sched/core.c:736
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1174
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:918
       cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6759
       copy_process+0x3862/0x3c00 kernel/fork.c:2417
       kernel_clone+0x21e/0x840 kernel/fork.c:2603
       user_mode_thread+0xdd/0x140 kernel/fork.c:2681
       rest_init+0x23/0x300 init/main.c:709
       start_kernel+0x3a9/0x410 init/main.c:1097
       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

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
       try_to_wake_up+0x67/0x12b0 kernel/sched/core.c:4216
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1728
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1836
       serial8250_default_handle_irq+0xbf/0x1e0 drivers/tty/serial/8250/8250_port.c:1856
       serial8250_interrupt+0x8d/0x160 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x28c/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+0x23b/0xa10 kernel/irq/chip.c:855
       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+0x143/0x250 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:757
       default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e8/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
       common_startup_64+0x13e/0x147

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       __wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1728
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1836
       serial8250_default_handle_irq+0xbf/0x1e0 drivers/tty/serial/8250/8250_port.c:1856
       serial8250_interrupt+0x8d/0x160 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x28c/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+0x23b/0xa10 kernel/irq/chip.c:855
       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+0x143/0x250 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:757
       default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e8/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
       common_startup_64+0x13e/0x147

-> #1 (&port_lock_key){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __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_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3355
       console_emit_next_record kernel/printk/printk.c:3138 [inline]
       console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
       vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
       _printk+0xcf/0x120 kernel/printk/printk.c:2475
       register_console+0xa8b/0xf90 kernel/printk/printk.c:4125
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:516
       console_init+0x10e/0x430 kernel/printk/printk.c:4323
       start_kernel+0x254/0x410 init/main.c:1035
       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

-> #0 (console_owner){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       console_lock_spinning_enable kernel/printk/printk.c:1924 [inline]
       console_emit_next_record kernel/printk/printk.c:3132 [inline]
       console_flush_all+0x6d2/0xc40 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
       vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
       _printk+0xcf/0x120 kernel/printk/printk.c:2475
       fail_dump lib/fault-inject.c:66 [inline]
       should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
       strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
       ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline]
       bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:221
       bpf_prog_bc7c5c6b9645592f+0x3e/0x44
       bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
       __bpf_prog_run include/linux/filter.h:718 [inline]
       bpf_prog_run include/linux/filter.h:725 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
       bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2300
       __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
       __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220
       __do_trace_sched_switch include/trace/events/sched.h:220 [inline]
       trace_sched_switch include/trace/events/sched.h:220 [inline]
       __schedule+0x238f/0x4cc0 kernel/sched/core.c:6958
       preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
       irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
       asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
       arch_atomic64_read arch/x86/include/asm/atomic64_64.h:15 [inline]
       raw_atomic64_read include/linux/atomic/atomic-arch-fallback.h:2583 [inline]
       raw_atomic_long_read include/linux/atomic/atomic-long.h:38 [inline]
       atomic_long_read include/linux/atomic/atomic-instrumented.h:3189 [inline]
       __mutex_unlock_slowpath+0xff/0x760 kernel/locking/mutex.c:931
       fdput_pos include/linux/file.h:79 [inline]
       class_fd_pos_destructor include/linux/file.h:85 [inline]
       ksys_write+0x1cb/0x250 fs/read_write.c:744
       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:

Chain exists of:
  console_owner --> &p->pi_lock --> &rq->__lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&rq->__lock);
                               lock(&p->pi_lock);
                               lock(&rq->__lock);
  lock(console_owner);

 *** DEADLOCK ***

4 locks held by syz.1.355/7542:
 #0: ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:636
 #1: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #1: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline]
 #1: ffffffff8e139e60 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2300
 #2: ffffffff8e12e100 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2475
 #3: ffffffff8e0159d0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #3: ffffffff8e0159d0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
 #3: ffffffff8e0159d0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #3: ffffffff8e0159d0 (console_srcu){....}-{0:0}, at: console_flush_all+0x13a/0xc40 kernel/printk/printk.c:3203

stack backtrace:
CPU: 0 UID: 0 PID: 7542 Comm: syz.1.355 Not tainted 6.16.0-syzkaller-11105-ga6923c06a3b2 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 console_lock_spinning_enable kernel/printk/printk.c:1924 [inline]
 console_emit_next_record kernel/printk/printk.c:3132 [inline]
 console_flush_all+0x6d2/0xc40 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
 _printk+0xcf/0x120 kernel/printk/printk.c:2475
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline]
 bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:221
 bpf_prog_bc7c5c6b9645592f+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2300
 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220
 __do_trace_sched_switch include/trace/events/sched.h:220 [inline]
 trace_sched_switch include/trace/events/sched.h:220 [inline]
 __schedule+0x238f/0x4cc0 kernel/sched/core.c:6958
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:arch_atomic64_read arch/x86/include/asm/atomic64_64.h:-1 [inline]
RIP: 0010:raw_atomic64_read include/linux/atomic/atomic-arch-fallback.h:2583 [inline]
RIP: 0010:raw_atomic_long_read include/linux/atomic/atomic-long.h:38 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:3189 [inline]
RIP: 0010:__mutex_unlock_slowpath+0xff/0x760 kernel/locking/mutex.c:931
Code: f7 33 aa f6 4c 89 f8 48 c1 e8 03 48 89 44 24 28 42 80 3c 28 00 74 08 4c 89 ff e8 6c 31 aa f6 4c 8d a4 24 a0 00 00 00 49 8b 07 <49> c7 c6 40 b3 aa 99 49 c1 ee 03 48 c7 c3 74 55 a3 8f 48 c1 eb 03
RSP: 0018:ffffc9000395fd00 EFLAGS: 00000246
RAX: ffff88802687da00 RBX: ffff88802fb30e03 RCX: ffffffff8b78c089
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88802fb30e90
RBP: ffffc9000395fe10 R08: ffff88802fb30e97 R09: 1ffff11005f661d2
R10: dffffc0000000000 R11: ffffed1005f661d3 R12: ffffc9000395fda0
R13: dffffc0000000000 R14: ffffc9000395fd80 R15: ffff88802fb30e90
 fdput_pos include/linux/file.h:79 [inline]
 class_fd_pos_destructor include/linux/file.h:85 [inline]
 ksys_write+0x1cb/0x250 fs/read_write.c:744
 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
RIP: 0033:0x7fd6db78d61f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fd6dc62e030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007fd6db78d61f
RDX: 0000000000000001 RSI: 00007fd6dc62e090 RDI: 0000000000000009
RBP: 00007fd6dc62e090 R08: 0000000000000000 R09: 00007fd6dc62ddf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fd6db9b6160 R15: 00007ffcffa32a18
 </TASK>
CPU: 0 UID: 0 PID: 7542 Comm: syz.1.355 Not tainted 6.16.0-syzkaller-11105-ga6923c06a3b2 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x414/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x290 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:224 [inline]
 bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:221
 bpf_prog_bc7c5c6b9645592f+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1332 [inline]
 __bpf_prog_run include/linux/filter.h:718 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2300
 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x9d/0xd0 include/trace/events/sched.h:220
 __do_trace_sched_switch include/trace/events/sched.h:220 [inline]
 trace_sched_switch include/trace/events/sched.h:220 [inline]
 __schedule+0x238f/0x4cc0 kernel/sched/core.c:6958
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:arch_atomic64_read arch/x86/include/asm/atomic64_64.h:-1 [inline]
RIP: 0010:raw_atomic64_read include/linux/atomic/atomic-arch-fallback.h:2583 [inline]
RIP: 0010:raw_atomic_long_read include/linux/atomic/atomic-long.h:38 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:3189 [inline]
RIP: 0010:__mutex_unlock_slowpath+0xff/0x760 kernel/locking/mutex.c:931
Code: f7 33 aa f6 4c 89 f8 48 c1 e8 03 48 89 44 24 28 42 80 3c 28 00 74 08 4c 89 ff e8 6c 31 aa f6 4c 8d a4 24 a0 00 00 00 49 8b 07 <49> c7 c6 40 b3 aa 99 49 c1 ee 03 48 c7 c3 74 55 a3 8f 48 c1 eb 03
RSP: 0018:ffffc9000395fd00 EFLAGS: 00000246
RAX: ffff88802687da00 RBX: ffff88802fb30e03 RCX: ffffffff8b78c089
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88802fb30e90
RBP: ffffc9000395fe10 R08: ffff88802fb30e97 R09: 1ffff11005f661d2
R10: dffffc0000000000 R11: ffffed1005f661d3 R12: ffffc9000395fda0
R13: dffffc0000000000 R14: ffffc9000395fd80 R15: ffff88802fb30e90
 fdput_pos include/linux/file.h:79 [inline]
 class_fd_pos_destructor include/linux/file.h:85 [inline]
 ksys_write+0x1cb/0x250 fs/read_write.c:744
 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
RIP: 0033:0x7fd6db78d61f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fd6dc62e030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007fd6db78d61f
RDX: 0000000000000001 RSI: 00007fd6dc62e090 RDI: 0000000000000009
RBP: 00007fd6dc62e090 R08: 0000000000000000 R09: 00007fd6dc62ddf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fd6db9b6160 R15: 00007ffcffa32a18
 </TASK>
----------------
Code disassembly (best guess):
   0:	f7 33                	divl   (%rbx)
   2:	aa                   	stos   %al,%es:(%rdi)
   3:	f6 4c 89 f8 48       	testb  $0x48,-0x8(%rcx,%rcx,4)
   8:	c1 e8 03             	shr    $0x3,%eax
   b:	48 89 44 24 28       	mov    %rax,0x28(%rsp)
  10:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  15:	74 08                	je     0x1f
  17:	4c 89 ff             	mov    %r15,%rdi
  1a:	e8 6c 31 aa f6       	call   0xf6aa318b
  1f:	4c 8d a4 24 a0 00 00 	lea    0xa0(%rsp),%r12
  26:	00
  27:	49 8b 07             	mov    (%r15),%rax
* 2a:	49 c7 c6 40 b3 aa 99 	mov    $0xffffffff99aab340,%r14 <-- trapping instruction
  31:	49 c1 ee 03          	shr    $0x3,%r14
  35:	48 c7 c3 74 55 a3 8f 	mov    $0xffffffff8fa35574,%rbx
  3c:	48 c1 eb 03          	shr    $0x3,%rbx