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.2.2144/9724 is trying to acquire lock:
ffffffff8cb1ee60 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8cb1ee60 (console_owner){-...}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774

but task is already holding lock:
ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537

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+0x2e/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
       raw_spin_rq_lock kernel/sched/sched.h:1355 [inline]
       rq_lock kernel/sched/sched.h:1645 [inline]
       task_fork_fair+0x5c/0x350 kernel/sched/fair.c:11901
       sched_cgroup_fork+0x32c/0x3c0 kernel/sched/core.c:4685
       copy_process+0x24b8/0x4020 kernel/fork.c:2459
       kernel_clone+0x225/0x8b0 kernel/fork.c:2757
       user_mode_thread+0xda/0x130 kernel/fork.c:2833
       rest_init+0x23/0x300 init/main.c:710
       start_kernel+0x0/0x539 init/main.c:905
       start_kernel+0x490/0x539 init/main.c:1152
       secondary_startup_64_no_verify+0xcf/0xdb

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       try_to_wake_up+0x5c/0x1080 kernel/sched/core.c:4111
       __wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:107
       __wake_up_common_lock kernel/sched/wait.c:138 [inline]
       __wake_up+0x10e/0x190 kernel/sched/wait.c:160
       tty_port_default_wakeup+0x9e/0xf0 drivers/tty/tty_port.c:71
       serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1854
       serial8250_handle_irq+0x516/0x6d0 drivers/tty/serial/8250/8250_port.c:1961
       serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1981
       serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x298/0xa30 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x87/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:233 [inline]
       __common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
       common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682
       PageTail include/linux/page-flags.h:292 [inline]
       folio_memcg_kmem include/linux/memcontrol.h:541 [inline]
       folio_memcg+0x22/0x130 include/linux/memcontrol.h:435
       folio_memcg_unlock mm/memcontrol.c:2164 [inline]
       unlock_page_memcg+0x3d/0xb0 mm/memcontrol.c:2169
       page_add_file_rmap+0x8d8/0x1500 mm/rmap.c:1331
       do_set_pte+0x2f4/0x460 mm/memory.c:4424
       filemap_map_pages+0xcab/0x10d0 mm/filemap.c:3481
       do_fault_around mm/memory.c:4600 [inline]
       do_read_fault mm/memory.c:4626 [inline]
       do_fault mm/memory.c:4760 [inline]
       handle_pte_fault mm/memory.c:5031 [inline]
       __handle_mm_fault mm/memory.c:5173 [inline]
       handle_mm_fault+0x287e/0x3e60 mm/memory.c:5294
       do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1340
       handle_page_fault arch/x86/mm/fault.c:1431 [inline]
       exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1487
       asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608

-> #2 (&tty->write_wait){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       __wake_up_common_lock kernel/sched/wait.c:137 [inline]
       __wake_up+0xf4/0x190 kernel/sched/wait.c:160
       tty_port_default_wakeup+0x9e/0xf0 drivers/tty/tty_port.c:71
       serial8250_tx_chars+0x629/0x830 drivers/tty/serial/8250/8250_port.c:1854
       serial8250_handle_irq+0x516/0x6d0 drivers/tty/serial/8250/8250_port.c:1961
       serial8250_default_handle_irq+0xb4/0x1a0 drivers/tty/serial/8250/8250_port.c:1981
       serial8250_interrupt+0x9b/0x1c0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x298/0xa30 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x87/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x243/0xb20 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:233 [inline]
       __common_interrupt+0xd7/0x1e0 arch/x86/kernel/irq.c:252
       common_interrupt+0xb0/0xd0 arch/x86/kernel/irq.c:242
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682
       native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
       default_idle+0xb/0x10 arch/x86/kernel/process.c:741
       default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
       cpuidle_idle_call kernel/sched/idle.c:191 [inline]
       do_idle+0x1fc/0x570 kernel/sched/idle.c:303
       cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
       rest_init+0x2dc/0x300 init/main.c:745
       start_kernel+0x0/0x539 init/main.c:905
       start_kernel+0x490/0x539 init/main.c:1152
       secondary_startup_64_no_verify+0xcf/0xdb

-> #1 (&port_lock_key){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
       serial8250_console_write+0x169/0x17a0 drivers/tty/serial/8250/8250_port.c:3432
       call_console_driver kernel/printk/printk.c:1977 [inline]
       console_emit_next_record+0x947/0xc90 kernel/printk/printk.c:2777
       console_flush_all kernel/printk/printk.c:-1 [inline]
       console_unlock+0x223/0x630 kernel/printk/printk.c:2906
       vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
       _printk+0xcc/0x110 kernel/printk/printk.c:2328
       register_console+0x6c6/0x9c0 kernel/printk/printk.c:3269
       univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:687
       console_init+0x1bc/0x78e kernel/printk/printk.c:3359
       start_kernel+0x303/0x539 init/main.c:1088
       secondary_startup_64_no_verify+0xcf/0xdb

-> #0 (console_owner){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
       console_emit_next_record+0x84c/0xc90 kernel/printk/printk.c:2774
       console_flush_all kernel/printk/printk.c:-1 [inline]
       console_unlock+0x223/0x630 kernel/printk/printk.c:2906
       vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
       _printk+0xcc/0x110 kernel/printk/printk.c:2328
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail_ex+0x37a/0x4d0 lib/fault-inject.c:147
       strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
       bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
       bpf_prog_2d403b9db727cc7e+0x3d/0x41
       bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
       __bpf_prog_run include/linux/filter.h:603 [inline]
       bpf_prog_run include/linux/filter.h:610 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
       bpf_trace_run4+0x1f5/0x420 kernel/trace/bpf_trace.c:2326
       __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
       schedule+0xb9/0x180 kernel/sched/core.c:6637
       exit_to_user_mode_loop+0x47/0x110 kernel/entry/common.c:165
       exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
       irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
       asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691

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 ***

3 locks held by syz.2.2144/9724:
 #0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #1: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #1: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xf9/0x420 kernel/trace/bpf_trace.c:2326
 #2: ffffffff8cb1ef40 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328

stack backtrace:
CPU: 1 PID: 9724 Comm: syz.2.2144 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
 console_emit_next_record+0x84c/0xc90 kernel/printk/printk.c:2774
 console_flush_all kernel/printk/printk.c:-1 [inline]
 console_unlock+0x223/0x630 kernel/printk/printk.c:2906
 vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303
 _printk+0xcc/0x110 kernel/printk/printk.c:2328
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail_ex+0x37a/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_2d403b9db727cc7e+0x3d/0x41
 bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run4+0x1f5/0x420 kernel/trace/bpf_trace.c:2326
 __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 exit_to_user_mode_loop+0x47/0x110 kernel/entry/common.c:165
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fbb0eba9c60
Code: 44 89 c1 23 48 0c 48 8d 0c 88 8b 14 11 85 d2 74 0a 23 70 10 48 8d 04 b0 8b 3c 10 89 f8 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 <48> 89 1f 48 89 e8 64 48 33 04 25 30 00 00 00 48 c1 c0 11 48 89 47
RSP: 002b:00007fbb0fac6058 EFLAGS: 00000246
RAX: 00007fbb0fac66c0 RBX: 0000000000000008 RCX: 0000000000000000
RDX: 00007fbb0fac6090 RSI: 0000000000000000 RDI: 00007fbb0fac6588
RBP: 00007fbb0fac6090 R08: 0000000000000000 R09: 00007fbb0fac5df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007fbb0ede6038 R14: 00007fbb0ede5fa0 R15: 00007ffc7dec65e8
 </TASK>
CPU: 1 PID: 9724 Comm: syz.2.2144 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail_ex+0x399/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x350 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6d/0x140 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:204 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xdd/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_2d403b9db727cc7e+0x3d/0x41
 bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2285 [inline]
 bpf_trace_run4+0x1f5/0x420 kernel/trace/bpf_trace.c:2326
 __traceiter_sched_switch+0x8f/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x1d18/0x40b0 kernel/sched/core.c:6558
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 exit_to_user_mode_loop+0x47/0x110 kernel/entry/common.c:165
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0033:0x7fbb0eba9c60
Code: 44 89 c1 23 48 0c 48 8d 0c 88 8b 14 11 85 d2 74 0a 23 70 10 48 8d 04 b0 8b 3c 10 89 f8 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 <48> 89 1f 48 89 e8 64 48 33 04 25 30 00 00 00 48 c1 c0 11 48 89 47
RSP: 002b:00007fbb0fac6058 EFLAGS: 00000246
RAX: 00007fbb0fac66c0 RBX: 0000000000000008 RCX: 0000000000000000
RDX: 00007fbb0fac6090 RSI: 0000000000000000 RDI: 00007fbb0fac6588
RBP: 00007fbb0fac6090 R08: 0000000000000000 R09: 00007fbb0fac5df7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007fbb0ede6038 R14: 00007fbb0ede5fa0 R15: 00007ffc7dec65e8
 </TASK>
------------[ cut here ]------------
WARNING: CPU: 0 PID: 9724 at kernel/events/core.c:6592 perf_sigtrap kernel/events/core.c:6592 [inline]
WARNING: CPU: 0 PID: 9724 at kernel/events/core.c:6592 perf_pending_task+0x358/0x470 kernel/events/core.c:6704
Modules linked in:
CPU: 0 PID: 9724 Comm: syz.2.2144 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:perf_sigtrap kernel/events/core.c:6592 [inline]
RIP: 0010:perf_pending_task+0x358/0x470 kernel/events/core.c:6704
Code: ff 84 db 75 14 e8 b8 d1 da ff 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 a4 d1 da ff e8 f7 7b 5a ff eb e5 e8 98 d1 da ff <0f> 0b e9 f3 fe ff ff e8 8c d1 da ff 48 c7 c7 d0 03 bc 8c 4c 89 f6
RSP: 0018:ffffc9000d8ef900 EFLAGS: 00010293
RAX: ffffffff81a604c8 RBX: ffff88805708fc58 RCX: ffff8880500d0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffed100a01a141
R10: ffffed100a01a141 R11: 1ffff1100a01a140 R12: ffff8880500d0000
R13: ffff888056177960 R14: ffff88805708fa20 R15: 1ffff1100ae11f44
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000b CR3: 000000005f1c2000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbb0ebb7e00
Code: Unable to access opcode bytes at 0x7fbb0ebb7dd6.
RSP: 002b:00007fbb0fac4c78 EFLAGS: 00000283
RAX: 0000000000000000 RBX: 00007fbb0fac5d30 RCX: 00007fbb0eda8120
RDX: 00007fbb0fac4c80 RSI: 00007fbb0fac4db0 RDI: 0000000000000021
RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000073
R13: 00007fbb0fac5eb0 R14: 9999999999999999 R15: 0000000000000000
 </TASK>