FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.6.4078/17918 is trying to acquire lock:
ffffffff8dd2e920 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
ffffffff8dd2e920 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
ffffffff8dd2e920 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
ffffffff8dd2e920 (console_owner){-...}-{0:0}, at: console_flush_all+0x13a/0xc40 kernel/printk/printk.c:3203

but task is already holding lock:
ffff8880b8839fd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638

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:638
       raw_spin_rq_lock kernel/sched/sched.h:1546 [inline]
       task_rq_lock+0xbc/0x470 kernel/sched/core.c:738
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:951
       cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6913
       copy_process+0x3862/0x3c00 kernel/fork.c:2424
       kernel_clone+0x21e/0x840 kernel/fork.c:2610
       user_mode_thread+0xdd/0x140 kernel/fork.c:2688
       rest_init+0x23/0x300 init/main.c:710
       start_kernel+0x3ae/0x410 init/main.c:1099
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       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:4181
       __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+0x292/0xab0 kernel/irq/handle.c:203
       handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
       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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
       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+0x73/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e7/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       rest_init+0x2de/0x300 init/main.c:745
       start_kernel+0x3ae/0x410 init/main.c:1099
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       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+0x292/0xab0 kernel/irq/handle.c:203
       handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
       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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
       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+0x73/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e7/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       rest_init+0x2de/0x300 init/main.c:745
       start_kernel+0x3ae/0x410 init/main.c:1099
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       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:4126
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:516
       console_init+0x10e/0x430 kernel/printk/printk.c:4325
       start_kernel+0x254/0x410 init/main.c:1036
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       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:214 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
       bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
       bpf_prog_573c5a647519ba93+0x3e/0x44
       bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
       __bpf_prog_run include/linux/filter.h:721 [inline]
       bpf_prog_run include/linux/filter.h:728 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
       bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
       __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
       __traceiter_sched_switch+0x9a/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:6926
       preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
       irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
       asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
       skb_dst+0x0/0xd0 drivers/net/vrf.c:-1
       dst_output+0x10a/0x1c0 include/net/dst.h:461
       ip_local_out net/ipv4/ip_output.c:129 [inline]
       __ip_queue_xmit+0x1106/0x1b00 net/ipv4/ip_output.c:532
       l2tp_ip_sendmsg+0x663/0x1650 net/l2tp/l2tp_ip.c:518
       sock_sendmsg_nosec net/socket.c:714 [inline]
       __sock_sendmsg+0x19c/0x270 net/socket.c:729
       ____sys_sendmsg+0x505/0x830 net/socket.c:2617
       ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671
       __sys_sendmsg net/socket.c:2703 [inline]
       __do_sys_sendmsg net/socket.c:2708 [inline]
       __se_sys_sendmsg net/socket.c:2706 [inline]
       __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706
       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 ***

7 locks held by syz.6.4078/17918:
 #0: ffff888054125658 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline]
 #0: ffff888054125658 (sk_lock-AF_INET){+.+.}-{0:0}, at: l2tp_ip_sendmsg+0x34/0x1650 net/l2tp/l2tp_ip.c:431
 #1: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #1: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: l2tp_ip_sendmsg+0x43e/0x1650 net/l2tp/l2tp_ip.c:486
 #2: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #2: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: __ip_queue_xmit+0x63/0x1b00 net/ipv4/ip_output.c:475
 #3: ffff8880b8839fd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
 #4: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #4: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #4: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #4: ffffffff8dd3a960 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2118
 #5: ffffffff8dd2e980 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2475
 #6: ffffffff8dc16250 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #6: ffffffff8dc16250 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
 #6: ffffffff8dc16250 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #6: ffffffff8dc16250 (console_srcu){....}-{0:0}, at: console_flush_all+0x13a/0xc40 kernel/printk/printk.c:3203

stack backtrace:
CPU: 0 UID: 0 PID: 17918 Comm: syz.6.4078 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_573c5a647519ba93+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x9a/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:6926
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:skb_dst+0x0/0xd0 include/linux/skbuff.h:1152
Code: 89 f0 eb 8d 89 d9 80 e1 07 80 c1 03 38 c1 7c c3 48 89 df e8 f2 f0 77 f8 eb b9 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 54 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8
RSP: 0018:ffffc9000b2e7858 EFLAGS: 00000283
RAX: ffffffff89aa33e0 RBX: ffff888060a368c0 RCX: ffff888060301e40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060a368c0
RBP: ffff88805cd15400 R08: ffff888060301e40 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: ffff88805cd15430
R13: dffffc0000000000 R14: ffff888060a36918 R15: ffff888026b94900
 dst_output+0x10a/0x1c0 include/net/dst.h:461
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0x1106/0x1b00 net/ipv4/ip_output.c:532
 l2tp_ip_sendmsg+0x663/0x1650 net/l2tp/l2tp_ip.c:518
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x19c/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2617
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671
 __sys_sendmsg net/socket.c:2703 [inline]
 __do_sys_sendmsg net/socket.c:2708 [inline]
 __se_sys_sendmsg net/socket.c:2706 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706
 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: 0033:0x7f401458eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f401548d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f40147e5fa0 RCX: 00007f401458eec9
RDX: 0900000000000000 RSI: 0000200000000500 RDI: 0000000000000003
RBP: 00007f401548d090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f40147e6038 R14: 00007f40147e5fa0 R15: 00007fff04345458
 </TASK>
CPU: 0 UID: 0 PID: 17918 Comm: syz.6.4078 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:214 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:309 [inline]
 bpf_probe_read_compat_str+0xe2/0x180 kernel/trace/bpf_trace.c:305
 bpf_prog_573c5a647519ba93+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
 __bpf_trace_sched_switch+0x17a/0x1e0 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x9a/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:6926
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:skb_dst+0x0/0xd0 include/linux/skbuff.h:1152
Code: 89 f0 eb 8d 89 d9 80 e1 07 80 c1 03 38 c1 7c c3 48 89 df e8 f2 f0 77 f8 eb b9 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 54 53 48 89 fb 49 be 00 00 00 00 00 fc ff df e8
RSP: 0018:ffffc9000b2e7858 EFLAGS: 00000283
RAX: ffffffff89aa33e0 RBX: ffff888060a368c0 RCX: ffff888060301e40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060a368c0
RBP: ffff88805cd15400 R08: ffff888060301e40 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: ffff88805cd15430
R13: dffffc0000000000 R14: ffff888060a36918 R15: ffff888026b94900
 dst_output+0x10a/0x1c0 include/net/dst.h:461
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 __ip_queue_xmit+0x1106/0x1b00 net/ipv4/ip_output.c:532
 l2tp_ip_sendmsg+0x663/0x1650 net/l2tp/l2tp_ip.c:518
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x19c/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2617
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671
 __sys_sendmsg net/socket.c:2703 [inline]
 __do_sys_sendmsg net/socket.c:2708 [inline]
 __se_sys_sendmsg net/socket.c:2706 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706
 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: 0033:0x7f401458eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f401548d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f40147e5fa0 RCX: 00007f401458eec9
RDX: 0900000000000000 RSI: 0000200000000500 RDI: 0000000000000003
RBP: 00007f401548d090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f40147e6038 R14: 00007f40147e5fa0 R15: 00007fff04345458
 </TASK>
----------------
Code disassembly (best guess):
   0:	89 f0                	mov    %esi,%eax
   2:	eb 8d                	jmp    0xffffff91
   4:	89 d9                	mov    %ebx,%ecx
   6:	80 e1 07             	and    $0x7,%cl
   9:	80 c1 03             	add    $0x3,%cl
   c:	38 c1                	cmp    %al,%cl
   e:	7c c3                	jl     0xffffffd3
  10:	48 89 df             	mov    %rbx,%rdi
  13:	e8 f2 f0 77 f8       	call   0xf877f10a
  18:	eb b9                	jmp    0xffffffd3
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
  27:	90                   	nop
  28:	90                   	nop
  29:	90                   	nop
* 2a:	55                   	push   %rbp <-- trapping instruction
  2b:	41 57                	push   %r15
  2d:	41 56                	push   %r14
  2f:	41 54                	push   %r12
  31:	53                   	push   %rbx
  32:	48 89 fb             	mov    %rdi,%rbx
  35:	49 be 00 00 00 00 00 	movabs $0xdffffc0000000000,%r14
  3c:	fc ff df
  3f:	e8                   	.byte 0xe8