FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.15.0-syzkaller-12463-g0097c4195b1d #0 Not tainted
------------------------------------------------------
syz.1.933/8303 is trying to acquire lock:
ffffffff8e133280 (console_owner){-...}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2048 [inline]
ffffffff8e133280 (console_owner){-...}-{0:0}, at: vprintk_emit+0x444/0x7a0 kernel/printk/printk.c:2449

but task is already holding lock:
ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606

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:5871
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
       raw_spin_rq_lock kernel/sched/sched.h:1532 [inline]
       task_rq_lock+0xbc/0x470 kernel/sched/core.c:708
       cgroup_move_task+0x9a/0x590 kernel/sched/psi.c:1161
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:918
       cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6754
       copy_process+0x3862/0x3c00 kernel/fork.c:2413
       kernel_clone+0x21e/0x870 kernel/fork.c:2599
       user_mode_thread+0xdd/0x140 kernel/fork.c:2677
       rest_init+0x23/0x300 init/main.c:709
       start_kernel+0x47d/0x500 init/main.c:1101
       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:5871
       __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+0x6e/0x1290 kernel/sched/core.c:4226
       __wake_up_common kernel/sched/wait.c:89 [inline]
       __wake_up_common_lock+0x134/0x1f0 kernel/sched/wait.c:106
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1842
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1950
       serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1970
       serial8250_interrupt+0xa2/0x1d0 drivers/tty/serial/8250/8250_core.c:86
       __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+0x267/0x9c0 kernel/irq/chip.c:789
       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:743
       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:744
       start_kernel+0x47d/0x500 init/main.c:1101
       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

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       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
       __wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:105
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:69
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1842
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1950
       serial8250_default_handle_irq+0xbf/0x1b0 drivers/tty/serial/8250/8250_port.c:1970
       serial8250_interrupt+0xa2/0x1d0 drivers/tty/serial/8250/8250_core.c:86
       __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+0x267/0x9c0 kernel/irq/chip.c:789
       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:743
       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:744
       start_kernel+0x47d/0x500 init/main.c:1101
       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

-> #1 (&port_lock_key){-.-.}-{3:3}:
       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:715 [inline]
       serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3415
       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+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: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:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       console_trylock_spinning kernel/printk/printk.c:2048 [inline]
       vprintk_emit+0x460/0x7a0 kernel/printk/printk.c:2449
       _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:193
       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_9deb4dd9eeaa7b3b+0x46/0x4e
       bpf_dispatcher_nop_func include/linux/bpf.h:1322 [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:2258 [inline]
       bpf_trace_run4+0x28b/0x4a0 kernel/trace/bpf_trace.c:2301
       __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+0x2328/0x4d00 kernel/sched/core.c:6782
       __schedule_loop kernel/sched/core.c:6863 [inline]
       schedule+0x165/0x360 kernel/sched/core.c:6878
       exit_to_user_mode_loop kernel/entry/common.c:102 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
       irqentry_exit_to_user_mode+0x5d/0x120 kernel/entry/common.c:184
       asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

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 ***

2 locks held by syz.1.933/8303:
 #0: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
 #1: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #1: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
 #1: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2301

stack backtrace:
CPU: 0 UID: 0 PID: 8303 Comm: syz.1.933 Not tainted 6.15.0-syzkaller-12463-g0097c4195b1d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 console_trylock_spinning kernel/printk/printk.c:2048 [inline]
 vprintk_emit+0x460/0x7a0 kernel/printk/printk.c:2449
 _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:193
 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_9deb4dd9eeaa7b3b+0x46/0x4e
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [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:2258 [inline]
 bpf_trace_run4+0x28b/0x4a0 kernel/trace/bpf_trace.c:2301
 __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+0x2328/0x4d00 kernel/sched/core.c:6782
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 exit_to_user_mode_loop kernel/entry/common.c:102 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 irqentry_exit_to_user_mode+0x5d/0x120 kernel/entry/common.c:184
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0033:0x7f7c5f18d3df
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:00007f7c5ff63030 EFLAGS: 00000293
RAX: 0000000000000001 RBX: 0000000000000004 RCX: 00007f7c5f18d3df
RDX: 0000000000000001 RSI: 00007f7c5ff63090 RDI: 0000000000000004
RBP: 00007f7c5ff63090 R08: 0000000000000000 R09: 00007f7c5ff62df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f7c5f3b5fa0 R15: 00007ffebb390e98
 </TASK>
CPU: 0 UID: 0 PID: 8303 Comm: syz.1.933 Not tainted 6.15.0-syzkaller-12463-g0097c4195b1d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:193
 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_9deb4dd9eeaa7b3b+0x46/0x4e
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [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:2258 [inline]
 bpf_trace_run4+0x28b/0x4a0 kernel/trace/bpf_trace.c:2301
 __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+0x2328/0x4d00 kernel/sched/core.c:6782
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 exit_to_user_mode_loop kernel/entry/common.c:102 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 irqentry_exit_to_user_mode+0x5d/0x120 kernel/entry/common.c:184
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0033:0x7f7c5f18d3df
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:00007f7c5ff63030 EFLAGS: 00000293
RAX: 0000000000000001 RBX: 0000000000000004 RCX: 00007f7c5f18d3df
RDX: 0000000000000001 RSI: 00007f7c5ff63090 RDI: 0000000000000004
RBP: 00007f7c5ff63090 R08: 0000000000000000 R09: 00007f7c5ff62df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f7c5f3b5fa0 R15: 00007ffebb390e98
 </TASK>
netlink: 'syz.1.933': attribute type 29 has an invalid length.