FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.8.5799/30825 is trying to acquire lock:
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:317 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3194 [inline]
ffffffff8e138b80 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3291

but task is already holding lock:
ffff8880b863abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:647
       raw_spin_rq_lock kernel/sched/sched.h:1613 [inline]
       _task_rq_lock+0xbc/0x470 kernel/sched/core.c:747
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:948
       cgroup_post_fork+0x1ef/0x7a0 kernel/cgroup/cgroup.c:6910
       copy_process+0x385e/0x3ba0 kernel/fork.c:2462
       kernel_clone+0x21e/0x820 kernel/fork.c:2648
       user_mode_thread+0xdd/0x140 kernel/fork.c:2724
       rest_init+0x23/0x300 init/main.c:725
       start_kernel+0x386/0x3d0 init/main.c:1210
       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}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:573 [inline]
       try_to_wake_up+0x67/0x12c0 kernel/sched/core.c:4129
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
       pty_close+0x296/0x4a0 drivers/tty/pty.c:67
       tty_release+0x389/0x1720 drivers/tty/tty_io.c:1745
       __fput+0x44c/0xa70 fs/file_table.c:468
       task_work_run+0x1d4/0x260 kernel/task_work.c:233
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
       exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75
       __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
       syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
       syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
       do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       __wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x217/0x970 kernel/irq/handle.c:209
       handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
       handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
       generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
       handle_irq arch/x86/kernel/irq.c:262 [inline]
       call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:333
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:326
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
       _raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194
       spin_unlock_irqrestore include/linux/spinlock.h:410 [inline]
       uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
       uart_port_unlock_deref+0x111/0x2f0 drivers/tty/serial/serial_core.c:91
       uart_write+0xe8/0x130 drivers/tty/serial/serial_core.c:634
       process_output_block drivers/tty/n_tty.c:557 [inline]
       n_tty_write+0xd78/0x12a0 drivers/tty/n_tty.c:2366
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write+0x559/0xa20 drivers/tty/tty_io.c:1081
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x5c9/0xb30 fs/read_write.c:688
       ksys_write+0x145/0x250 fs/read_write.c:740
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&port_lock_key){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
       _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
       serial8250_console_write+0x155/0x1b60 drivers/tty/serial/8250/8250_port.c:3301
       console_emit_next_record kernel/printk/printk.c:3131 [inline]
       console_flush_one_record kernel/printk/printk.c:3217 [inline]
       console_flush_all+0x713/0xb00 kernel/printk/printk.c:3291
       __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
       vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
       _printk+0xcf/0x120 kernel/printk/printk.c:2453
       register_console+0xa8b/0xf90 kernel/printk/printk.c:4172
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:515
       console_init+0xfc/0x3f0 kernel/printk/printk.c:4371
       start_kernel+0x22c/0x3d0 init/main.c:1147
       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 kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
       console_emit_next_record kernel/printk/printk.c:3125 [inline]
       console_flush_one_record kernel/printk/printk.c:3217 [inline]
       console_flush_all+0x6bc/0xb00 kernel/printk/printk.c:3291
       __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
       vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
       _printk+0xcf/0x120 kernel/printk/printk.c:2453
       fail_dump lib/fault-inject.c:66 [inline]
       should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
       strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
       bpf_trace_copy_string kernel/bpf/helpers.c:755 [inline]
       bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976
       ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
       bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362
       bpf_prog_930ede9872f2967c+0x3e/0x44
       bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
       __bpf_prog_run include/linux/filter.h:723 [inline]
       bpf_prog_run include/linux/filter.h:730 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
       bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
       __bpf_trace_contention_begin+0xdc/0x130 include/trace/events/lock.h:95
       __do_trace_contention_begin include/trace/events/lock.h:95 [inline]
       trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95
       __pv_queued_spin_lock_slowpath+0xf0/0xad0 kernel/locking/qspinlock.c:219
       pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:35 [inline]
       queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:66 [inline]
       queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
       do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
       raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655
       raw_spin_rq_lock kernel/sched/sched.h:1613 [inline]
       rq_lock kernel/sched/sched.h:1943 [inline]
       __schedule+0x3bf/0x5030 kernel/sched/core.c:6806
       preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7229
       irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
       asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
       rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline]
       __rcu_read_unlock+0x33/0xe0 kernel/rcu/tree_plugin.h:435
       rcu_read_unlock include/linux/rcupdate.h:883 [inline]
       class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
       unwind_next_frame+0x1ab6/0x23d0 arch/x86/kernel/unwind_orc.c:695
       __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
       unwind_start arch/x86/include/asm/unwind.h:64 [inline]
       arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
       stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
       save_netdev_trace_buffer+0xd7/0x5a0 net/core/dev.c:13449
       __dev_hold include/linux/netdevice.h:4400 [inline]
       netdev_hold include/linux/netdevice.h:4443 [inline]
       dev_hold include/linux/netdevice.h:4466 [inline]
       __netlink_deliver_tap_skb net/netlink/af_netlink.c:295 [inline]
       __netlink_deliver_tap+0x25c/0x8b0 net/netlink/af_netlink.c:325
       netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338
       netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
       netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
       netlink_unicast+0x7fa/0x9e0 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
       sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
       __sock_sendmsg net/socket.c:752 [inline]
       ____sys_sendmsg+0x577/0x880 net/socket.c:2610
       ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
       __sys_sendmsg net/socket.c:2696 [inline]
       __do_sys_sendmsg net/socket.c:2701 [inline]
       __se_sys_sendmsg net/socket.c:2699 [inline]
       __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2699
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 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 ***

5 locks held by syz.8.5799/30825:
 #0: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: netlink_deliver_tap+0x2e/0x1b0 net/netlink/af_netlink.c:335
 #1: ffff8880b863abe0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655
 #2: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #2: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #2: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #2: ffffffff8e144ce0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x186/0x4c0 kernel/trace/bpf_trace.c:2116
 #3: ffffffff8e138be0 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2453
 #4: ffffffff8e020498 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:317 [inline]
 #4: ffffffff8e020498 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #4: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #4: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_flush_one_record kernel/printk/printk.c:3194 [inline]
 #4: ffffffff8e020498 (console_srcu){....}-{0:0}, at: console_flush_all+0x11a/0xb00 kernel/printk/printk.c:3291

stack backtrace:
CPU: 0 UID: 0 PID: 30825 Comm: syz.8.5799 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 console_lock_spinning_enable kernel/printk/printk.c:1902 [inline]
 console_emit_next_record kernel/printk/printk.c:3125 [inline]
 console_flush_one_record kernel/printk/printk.c:3217 [inline]
 console_flush_all+0x6bc/0xb00 kernel/printk/printk.c:3291
 __console_flush_and_unlock kernel/printk/printk.c:3321 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3361
 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2428
 _printk+0xcf/0x120 kernel/printk/printk.c:2453
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x3f5/0x560 lib/fault-inject.c:174
 strncpy_from_user+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_trace_copy_string kernel/bpf/helpers.c:755 [inline]
 bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976
 ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
 bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362
 bpf_prog_930ede9872f2967c+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_contention_begin+0xdc/0x130 include/trace/events/lock.h:95
 __do_trace_contention_begin include/trace/events/lock.h:95 [inline]
 trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95
 __pv_queued_spin_lock_slowpath+0xf0/0xad0 kernel/locking/qspinlock.c:219
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:35 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:66 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
 raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655
 raw_spin_rq_lock kernel/sched/sched.h:1613 [inline]
 rq_lock kernel/sched/sched.h:1943 [inline]
 __schedule+0x3bf/0x5030 kernel/sched/core.c:6806
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7229
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline]
RIP: 0010:__rcu_read_unlock+0x33/0xe0 kernel/rcu/tree_plugin.h:435
Code: 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25 08 70 a2 92 48 8d 9f 84 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 4f ff 0b 75 1d 4c 8d b7 88 04 00 00 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc90004e37248 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff88802adea2c4 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8db8bddd RDI: ffff88802ade9e40
RBP: dffffc0000000000 R08: ffffc90004e37398 R09: 0000000000000000
R10: ffffc90004e373f8 R11: fffff520009c6e81 R12: 1ffff110055bd458
R13: ffffc90004e30000 R14: ffffc90004e373a8 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:883 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x1ab6/0x23d0 arch/x86/kernel/unwind_orc.c:695
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_netdev_trace_buffer+0xd7/0x5a0 net/core/dev.c:13449
 __dev_hold include/linux/netdevice.h:4400 [inline]
 netdev_hold include/linux/netdevice.h:4443 [inline]
 dev_hold include/linux/netdevice.h:4466 [inline]
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:295 [inline]
 __netlink_deliver_tap+0x25c/0x8b0 net/netlink/af_netlink.c:325
 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338
 netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x7fa/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 ____sys_sendmsg+0x577/0x880 net/socket.c:2610
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
 __sys_sendmsg net/socket.c:2696 [inline]
 __do_sys_sendmsg net/socket.c:2701 [inline]
 __se_sys_sendmsg net/socket.c:2699 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2699
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd582f8f749
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:00007fd5811d5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd5831e6090 RCX: 00007fd582f8f749
RDX: 0000000020004000 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007fd5811d5090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd5831e6128 R14: 00007fd5831e6090 R15: 00007ffd29330588
 </TASK>
CPU: 0 UID: 0 PID: 30825 Comm: syz.8.5799 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 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+0x36/0x2c0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x72/0x150 mm/maccess.c:192
 bpf_trace_copy_string kernel/bpf/helpers.c:755 [inline]
 bpf_bprintf_prepare+0xbbc/0x13d0 kernel/bpf/helpers.c:976
 ____bpf_trace_printk kernel/trace/bpf_trace.c:372 [inline]
 bpf_trace_printk+0xdb/0x190 kernel/trace/bpf_trace.c:362
 bpf_prog_930ede9872f2967c+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1394 [inline]
 __bpf_prog_run include/linux/filter.h:723 [inline]
 bpf_prog_run include/linux/filter.h:730 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run2+0x284/0x4c0 kernel/trace/bpf_trace.c:2116
 __bpf_trace_contention_begin+0xdc/0x130 include/trace/events/lock.h:95
 __do_trace_contention_begin include/trace/events/lock.h:95 [inline]
 trace_contention_begin+0xfe/0x120 include/trace/events/lock.h:95
 __pv_queued_spin_lock_slowpath+0xf0/0xad0 kernel/locking/qspinlock.c:219
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:35 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:66 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
 raw_spin_rq_lock_nested+0xba/0x150 kernel/sched/core.c:655
 raw_spin_rq_lock kernel/sched/sched.h:1613 [inline]
 rq_lock kernel/sched/sched.h:1943 [inline]
 __schedule+0x3bf/0x5030 kernel/sched/core.c:6806
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7229
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline]
RIP: 0010:__rcu_read_unlock+0x33/0xe0 kernel/rcu/tree_plugin.h:435
Code: 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3c 25 08 70 a2 92 48 8d 9f 84 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 4f ff 0b 75 1d 4c 8d b7 88 04 00 00 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc90004e37248 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff88802adea2c4 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8db8bddd RDI: ffff88802ade9e40
RBP: dffffc0000000000 R08: ffffc90004e37398 R09: 0000000000000000
R10: ffffc90004e373f8 R11: fffff520009c6e81 R12: 1ffff110055bd458
R13: ffffc90004e30000 R14: ffffc90004e373a8 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:883 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x1ab6/0x23d0 arch/x86/kernel/unwind_orc.c:695
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_netdev_trace_buffer+0xd7/0x5a0 net/core/dev.c:13449
 __dev_hold include/linux/netdevice.h:4400 [inline]
 netdev_hold include/linux/netdevice.h:4443 [inline]
 dev_hold include/linux/netdevice.h:4466 [inline]
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:295 [inline]
 __netlink_deliver_tap+0x25c/0x8b0 net/netlink/af_netlink.c:325
 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338
 netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline]
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x7fa/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 ____sys_sendmsg+0x577/0x880 net/socket.c:2610
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2664
 __sys_sendmsg net/socket.c:2696 [inline]
 __do_sys_sendmsg net/socket.c:2701 [inline]
 __se_sys_sendmsg net/socket.c:2699 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2699
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd582f8f749
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:00007fd5811d5038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd5831e6090 RCX: 00007fd582f8f749
RDX: 0000000020004000 RSI: 0000200000000040 RDI: 0000000000000006
RBP: 00007fd5811d5090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd5831e6128 R14: 00007fd5831e6090 R15: 00007ffd29330588
 </TASK>
----------------
Code disassembly (best guess):
   0:	55                   	push   %rbp
   1:	41 54                	push   %r12
   3:	53                   	push   %rbx
   4:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
   b:	fc ff df
   e:	65 48 8b 3c 25 08 70 	mov    %gs:0xffffffff92a27008,%rdi
  15:	a2 92
  17:	48 8d 9f 84 04 00 00 	lea    0x484(%rdi),%rbx
  1e:	49 89 dc             	mov    %rbx,%r12
  21:	49 c1 ec 03          	shr    $0x3,%r12
  25:	43 0f b6 04 3c       	movzbl (%r12,%r15,1),%eax
* 2a:	84 c0                	test   %al,%al <-- trapping instruction
  2c:	75 4f                	jne    0x7d
  2e:	ff 0b                	decl   (%rbx)
  30:	75 1d                	jne    0x4f
  32:	4c 8d b7 88 04 00 00 	lea    0x488(%rdi),%r14
  39:	4c 89 f0             	mov    %r14,%rax
  3c:	48 c1 e8 03          	shr    $0x3,%rax