FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.148-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.5808/20273 is trying to acquire lock:
ffffffff8cb1ef80 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8cb1ef80 (console_owner){-.-.}-{0:0}, at: console_emit_next_record+0x82d/0xc90 kernel/printk/printk.c:2774

but task is already holding lock:
ffff8880b8e3aa98 (&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:11888
       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:698
       start_kernel+0x0/0x539 init/main.c:893
       start_kernel+0x490/0x539 init/main.c:1140
       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
       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:733
       start_kernel+0x0/0x539 init/main.c:893
       start_kernel+0x490/0x539 init/main.c:1140
       secondary_startup_64_no_verify+0xcf/0xdb

-> #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:733
       start_kernel+0x0/0x539 init/main.c:893
       start_kernel+0x490/0x539 init/main.c:1140
       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:3433
       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:1076
       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_user_str kernel/trace/bpf_trace.c:213 [inline]
       bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
       bpf_prog_7acee76fef7300d9+0x5b/0x5f
       bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
       trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
       switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
       context_switch kernel/sched/core.c:5229 [inline]
       __schedule+0xe99/0x40b0 kernel/sched/core.c:6561
       preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
       preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
       preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
       __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
       _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
       spin_unlock include/linux/spinlock.h:391 [inline]
       unix_stream_read_generic+0x124b/0x1f90 net/unix/af_unix.c:2834
       unix_stream_recvmsg+0x154/0x1a0 net/unix/af_unix.c:3008
       ____sys_recvmsg+0x292/0x580 net/socket.c:-1
       ___sys_recvmsg+0x1b2/0x510 net/socket.c:2780
       __sys_recvmsg net/socket.c:2810 [inline]
       __do_sys_recvmsg net/socket.c:2820 [inline]
       __se_sys_recvmsg net/socket.c:2817 [inline]
       __x64_sys_recvmsg+0x1eb/0x2b0 net/socket.c:2817
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

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.1.5808/20273:
 #0: ffff888056c95590 (&u->iolock){+.+.}-{3:3}, at: unix_stream_read_generic+0x145e/0x1f90 net/unix/af_unix.c:2851
 #1: ffff8880b8e3aa98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #2: ffffffff8cb2ade0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #2: ffffffff8cb2ade0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #2: ffffffff8cb2ade0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline]
 #2: ffffffff8cb2ade0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0xda/0x3b0 kernel/trace/bpf_trace.c:2324
 #3: ffffffff8cb1f060 (console_lock){+.+.}-{0:0}, at: _printk+0xcc/0x110 kernel/printk/printk.c:2328

stack backtrace:
CPU: 0 PID: 20273 Comm: syz.1.5808 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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_user_str kernel/trace/bpf_trace.c:213 [inline]
 bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
 bpf_prog_7acee76fef7300d9+0x5b/0x5f
 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
 trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
 switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5229 [inline]
 __schedule+0xe99/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 unix_stream_read_generic+0x124b/0x1f90 net/unix/af_unix.c:2834
 unix_stream_recvmsg+0x154/0x1a0 net/unix/af_unix.c:3008
 ____sys_recvmsg+0x292/0x580 net/socket.c:-1
 ___sys_recvmsg+0x1b2/0x510 net/socket.c:2780
 __sys_recvmsg net/socket.c:2810 [inline]
 __do_sys_recvmsg net/socket.c:2820 [inline]
 __se_sys_recvmsg net/socket.c:2817 [inline]
 __x64_sys_recvmsg+0x1eb/0x2b0 net/socket.c:2817
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6abb78ebe9
Code: Unable to access opcode bytes at 0x7f6abb78ebbf.
RSP: 002b:00007f6abc6db038 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f6abb9b5fa0 RCX: 00007f6abb78ebe9
RDX: 0000000000000002 RSI: 0000200000000500 RDI: 0000000000000009
RBP: 00007f6abc6db090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f6abb9b6038 R14: 00007f6abb9b5fa0 R15: 00007fffbaa7e7c8
 </TASK>
CPU: 0 PID: 20273 Comm: syz.1.5808 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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_user_str kernel/trace/bpf_trace.c:213 [inline]
 bpf_probe_read_user_str+0x26/0x70 kernel/trace/bpf_trace.c:210
 bpf_prog_7acee76fef7300d9+0x5b/0x5f
 bpf_dispatcher_nop_func include/linux/bpf.h:1001 [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_run2+0x1cd/0x3b0 kernel/trace/bpf_trace.c:2324
 trace_tlb_flush+0x143/0x190 include/trace/events/tlb.h:38
 switch_mm_irqs_off+0x758/0xb10 arch/x86/mm/tlb.c:-1
 context_switch kernel/sched/core.c:5229 [inline]
 __schedule+0xe99/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 unix_stream_read_generic+0x124b/0x1f90 net/unix/af_unix.c:2834
 unix_stream_recvmsg+0x154/0x1a0 net/unix/af_unix.c:3008
 ____sys_recvmsg+0x292/0x580 net/socket.c:-1
 ___sys_recvmsg+0x1b2/0x510 net/socket.c:2780
 __sys_recvmsg net/socket.c:2810 [inline]
 __do_sys_recvmsg net/socket.c:2820 [inline]
 __se_sys_recvmsg net/socket.c:2817 [inline]
 __x64_sys_recvmsg+0x1eb/0x2b0 net/socket.c:2817
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6abb78ebe9
Code: Unable to access opcode bytes at 0x7f6abb78ebbf.
RSP: 002b:00007f6abc6db038 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f6abb9b5fa0 RCX: 00007f6abb78ebe9
RDX: 0000000000000002 RSI: 0000200000000500 RDI: 0000000000000009
RBP: 00007f6abc6db090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f6abb9b6038 R14: 00007f6abb9b5fa0 R15: 00007fffbaa7e7c8
 </TASK>