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.2.1965/13736 is trying to acquire lock:
ffffffff8e4ce840 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable+0x9f/0xd0 kernel/printk/printk.c:1924

but task is already holding lock:
ffff8880b843a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline]
ffff8880b843a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629

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+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:636
       raw_spin_rq_lock kernel/sched/sched.h:1519 [inline]
       task_rq_lock+0xcf/0x490 kernel/sched/core.c:736
       cgroup_move_task+0x81/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:918
       cgroup_post_fork+0x201/0x9e0 kernel/cgroup/cgroup.c:6759
       copy_process+0x5cfa/0x7690 kernel/fork.c:2419
       kernel_clone+0xfc/0x930 kernel/fork.c:2605
       user_mode_thread+0xc7/0x110 kernel/fork.c:2683
       rest_init+0x23/0x2b0 init/main.c:709
       start_kernel+0x3ee/0x4d0 init/main.c:1097
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       common_startup_64+0x13e/0x148

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
       try_to_wake_up+0xb7/0x1870 kernel/sched/core.c:4216
       __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:108
       __wake_up_common_lock kernel/sched/wait.c:125 [inline]
       __wake_up+0x31/0x60 kernel/sched/wait.c:146
       tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1728
       serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1836
       serial8250_default_handle_irq+0x9a/0x250 drivers/tty/serial/8250/8250_port.c:1856
       serial8250_interrupt+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x3ca/0x9e0 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:310 [inline]
       __common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325
       common_interrupt+0x61/0xe0 arch/x86/kernel/irq.c:318
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
       variable_ffs arch/x86/include/asm/bitops.h:318 [inline]
       handle_softirqs+0x1dd/0x8e0 kernel/softirq.c:567
       __do_softirq kernel/softirq.c:613 [inline]
       invoke_softirq kernel/softirq.c:453 [inline]
       __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
       irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
       instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
       sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
       asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
       console_flush_all+0x9a2/0xc60 kernel/printk/printk.c:3227
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       kauditd_printk_skb kernel/audit.c:546 [inline]
       kauditd_hold_skb+0x205/0x250 kernel/audit.c:581
       kauditd_send_queue+0x239/0x290 kernel/audit.c:766
       kauditd_thread+0x623/0xa70 kernel/audit.c:890
       kthread+0x3c5/0x780 kernel/kthread.c:463
       ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       __wake_up_common_lock kernel/sched/wait.c:124 [inline]
       __wake_up+0x1c/0x60 kernel/sched/wait.c:146
       tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x68e/0x860 drivers/tty/serial/8250/8250_port.c:1728
       serial8250_handle_irq+0x761/0xcb0 drivers/tty/serial/8250/8250_port.c:1836
       serial8250_default_handle_irq+0x9a/0x250 drivers/tty/serial/8250/8250_port.c:1856
       serial8250_interrupt+0xf8/0x1b0 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x3ca/0x9e0 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:310 [inline]
       __common_interrupt+0xd0/0x2f0 arch/x86/kernel/irq.c:325
       common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:318
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
       _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
       spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
       uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
       uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline]
       uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline]
       uart_write+0x2a4/0xb30 drivers/tty/serial/serial_core.c:637
       process_output_block drivers/tty/n_tty.c:561 [inline]
       n_tty_write+0x41f/0x11e0 drivers/tty/n_tty.c:2377
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write.constprop.0+0x504/0x9b0 drivers/tty/tty_io.c:1081
       tty_write drivers/tty/tty_io.c:1102 [inline]
       redirected_tty_write drivers/tty/tty_io.c:1125 [inline]
       redirected_tty_write+0xd4/0x150 drivers/tty/tty_io.c:1105
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x7d0/0x11d0 fs/read_write.c:686
       ksys_write+0x12a/0x250 fs/read_write.c:738
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
       serial8250_console_write+0x181/0x1890 drivers/tty/serial/8250/8250_port.c:3355
       console_emit_next_record kernel/printk/printk.c:3138 [inline]
       console_flush_all+0x801/0xc60 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       register_console+0xc2d/0x11b0 kernel/printk/printk.c:4126
       univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:516
       console_init+0x14f/0x680 kernel/printk/printk.c:4325
       start_kernel+0x29f/0x4d0 init/main.c:1035
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       common_startup_64+0x13e/0x148

-> #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+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
       lock_acquire kernel/locking/lockdep.c:5868 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
       console_lock_spinning_enable+0xb0/0xd0 kernel/printk/printk.c:1924
       console_emit_next_record kernel/printk/printk.c:3132 [inline]
       console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       fail_dump lib/fault-inject.c:66 [inline]
       should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174
       strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x7f/0x180 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+0x26/0x70 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+0x252/0x5b0 kernel/trace/bpf_trace.c:2300
       __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220
       __traceiter_sched_switch+0x6f/0xc0 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+0x183b/0x5de0 kernel/sched/core.c:6958
       __schedule_loop kernel/sched/core.c:7043 [inline]
       schedule+0xe7/0x3a0 kernel/sched/core.c:7058
       exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:31
       exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
       syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
       do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
       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.2.1965/13736:
 #0: ffff8880b843a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:644 [inline]
 #0: ffff8880b843a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:629
 #1: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #1: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2256 [inline]
 #1: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x1d5/0x5b0 kernel/trace/bpf_trace.c:2300
 #2: ffffffff8e5aec80 (console_lock){+.+.}-{0:0}, at: _printk+0xc7/0x100 kernel/printk/printk.c:2475
 #3: ffffffff8e5aecf0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #3: ffffffff8e5aecf0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:319 [inline]
 #3: ffffffff8e5aecf0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #3: ffffffff8e5aecf0 (console_srcu){....}-{0:0}, at: console_flush_all+0x158/0xc60 kernel/printk/printk.c:3203

stack backtrace:
CPU: 0 UID: 0 PID: 13736 Comm: syz.2.1965 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2043
 check_noncircular+0x14c/0x170 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+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 console_lock_spinning_enable+0xb0/0xd0 kernel/printk/printk.c:1924
 console_emit_next_record kernel/printk/printk.c:3132 [inline]
 console_flush_all+0x7aa/0xc60 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
 vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
 _printk+0xc7/0x100 kernel/printk/printk.c:2475
 fail_dump lib/fault-inject.c:66 [inline]
 should_fail_ex+0x4e7/0x640 lib/fault-inject.c:174
 strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x7f/0x180 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+0x26/0x70 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+0x252/0x5b0 kernel/trace/bpf_trace.c:2300
 __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x6f/0xc0 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+0x183b/0x5de0 kernel/sched/core.c:6958
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:31
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f386418d69f
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:00007f3864f58030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: 0000000000000001 RBX: 0000000000000009 RCX: 00007f386418d69f
RDX: 0000000000000001 RSI: 00007f3864f58090 RDI: 0000000000000009
RBP: 00007f3864f58090 R08: 0000000000000000 R09: 00007f3864f57df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007f38643b6218 R14: 00007f38643b6180 R15: 00007fff41c1e698
 </TASK>
CPU: 0 UID: 0 PID: 13736 Comm: syz.2.1965 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x512/0x640 lib/fault-inject.c:174
 strncpy_from_user+0x3b/0x2e0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x7f/0x180 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+0x26/0x70 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+0x252/0x5b0 kernel/trace/bpf_trace.c:2300
 __bpf_trace_sched_switch+0x145/0x190 include/trace/events/sched.h:220
 __traceiter_sched_switch+0x6f/0xc0 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+0x183b/0x5de0 kernel/sched/core.c:6958
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 exit_to_user_mode_loop+0x67/0x110 kernel/entry/common.c:31
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f386418d69f
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:00007f3864f58030 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: 0000000000000001 RBX: 0000000000000009 RCX: 00007f386418d69f
RDX: 0000000000000001 RSI: 00007f3864f58090 RDI: 0000000000000009
RBP: 00007f3864f58090 R08: 0000000000000000 R09: 00007f3864f57df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007f38643b6218 R14: 00007f38643b6180 R15: 00007fff41c1e698
 </TASK>
netlink: 8 bytes leftover after parsing attributes in process `syz.2.1965'.