FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.1.129-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.2804/12574 is trying to acquire lock:
ffffffff8d322840 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
ffffffff8d322840 (console_owner){-...}-{0:0}, at: console_emit_next_record+0x74f/0xc30 kernel/printk/printk.c:2774

but task is already holding lock:
ffff8880b8f3a9d8 (&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}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       _raw_spin_lock_nested+0x2d/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+0x5d/0x350 kernel/sched/fair.c:11886
       sched_cgroup_fork+0x374/0x400 kernel/sched/core.c:4684
       copy_process+0x2482/0x40a0 kernel/fork.c:2383
       kernel_clone+0x222/0x920 kernel/fork.c:2681
       user_mode_thread+0x140/0x1b0 kernel/fork.c:2757
       rest_init+0x23/0x300 init/main.c:698
       start_kernel+0x0/0x53f init/main.c:893
       start_kernel+0x496/0x53f init/main.c:1140
       secondary_startup_64_no_verify+0xcf/0xdb

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       try_to_wake_up+0xad/0x1250 kernel/sched/core.c:4110
       __wake_up_common+0x2a0/0x4e0 kernel/sched/wait.c:107
       __wake_up_common_lock kernel/sched/wait.c:138 [inline]
       __wake_up+0x11a/0x1c0 kernel/sched/wait.c:160
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:71
       serial8250_tx_chars+0x60d/0x800 drivers/tty/serial/8250/8250_port.c:1854
       serial8250_handle_irq+0x4ff/0x6a0 drivers/tty/serial/8250/8250_port.c:1961
       serial8250_default_handle_irq+0xc8/0x1e0 drivers/tty/serial/8250/8250_port.c:1981
       serial8250_interrupt+0xa1/0x1e0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x2a8/0xb20 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x85/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x245/0xbf0 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:231 [inline]
       __common_interrupt+0xd7/0x1f0 arch/x86/kernel/irq.c:250
       common_interrupt+0xae/0xd0 arch/x86/kernel/irq.c:240
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682
       lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
       rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
       rcu_read_lock include/linux/rcupdate.h:791 [inline]
       page_ext_get+0x39/0x2a0 mm/page_ext.c:157
       page_table_check_clear+0x4b/0x6d0 mm/page_table_check.c:71
       zap_pte_range mm/memory.c:1435 [inline]
       zap_pmd_range mm/memory.c:1574 [inline]
       zap_pud_range mm/memory.c:1603 [inline]
       zap_p4d_range mm/memory.c:1624 [inline]
       unmap_page_range+0x1b4a/0x2740 mm/memory.c:1645
       unmap_vmas+0x48b/0x640 mm/memory.c:1730
       exit_mmap+0x249/0x980 mm/mmap.c:3238
       __mmput+0x115/0x3c0 kernel/fork.c:1200
       exit_mm+0x226/0x300 kernel/exit.c:565
       do_exit+0x9f1/0x26a0 kernel/exit.c:858
       do_group_exit+0x202/0x2b0 kernel/exit.c:1021
       __do_sys_exit_group kernel/exit.c:1032 [inline]
       __se_sys_exit_group kernel/exit.c:1030 [inline]
       __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1030
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (&tty->write_wait){-.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       __wake_up_common_lock kernel/sched/wait.c:137 [inline]
       __wake_up+0xfd/0x1c0 kernel/sched/wait.c:160
       tty_port_default_wakeup+0xa2/0xf0 drivers/tty/tty_port.c:71
       serial8250_tx_chars+0x60d/0x800 drivers/tty/serial/8250/8250_port.c:1854
       serial8250_handle_irq+0x4ff/0x6a0 drivers/tty/serial/8250/8250_port.c:1961
       serial8250_default_handle_irq+0xc8/0x1e0 drivers/tty/serial/8250/8250_port.c:1981
       serial8250_interrupt+0xa1/0x1e0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x2a8/0xb20 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0x85/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x245/0xbf0 kernel/irq/chip.c:819
       generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
       handle_irq arch/x86/kernel/irq.c:231 [inline]
       __common_interrupt+0xd7/0x1f0 arch/x86/kernel/irq.c:250
       common_interrupt+0xae/0xd0 arch/x86/kernel/irq.c:240
       asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:682
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
       _raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
       spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
       uart_write+0x66d/0x8d0 drivers/tty/serial/serial_core.c:602
       process_output_block drivers/tty/n_tty.c:586 [inline]
       n_tty_write+0xd7f/0x1260 drivers/tty/n_tty.c:2377
       do_tty_write drivers/tty/tty_io.c:1018 [inline]
       file_tty_write+0x504/0x890 drivers/tty/tty_io.c:1089
       call_write_iter include/linux/fs.h:2265 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x857/0xbc0 fs/read_write.c:584
       ksys_write+0x19c/0x2c0 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&port_lock_key){-.-.}-{2:2}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       serial8250_console_write+0x19f/0x1a30 drivers/tty/serial/8250/8250_port.c:3433
       call_console_driver kernel/printk/printk.c:1977 [inline]
       console_emit_next_record+0x86d/0xc30 kernel/printk/printk.c:2777
       console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906
       vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303
       _printk+0xd1/0x111 kernel/printk/printk.c:2328
       register_console+0x6b9/0x9a0 kernel/printk/printk.c:3269
       univ8250_console_init+0x41/0x43 drivers/tty/serial/8250/8250_core.c:687
       console_init+0x1d6/0x7f3 kernel/printk/printk.c:3359
       start_kernel+0x30b/0x53f 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
       console_emit_next_record+0x76c/0xc30 kernel/printk/printk.c:2774
       console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906
       vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303
       _printk+0xd1/0x111 kernel/printk/printk.c:2328
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147
       strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x6c/0x130 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+0xe4/0x180 kernel/trace/bpf_trace.c:306
       bpf_prog_c1796171ffc7efef+0x35/0x37
       bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
       bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
       __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x2128/0x4570 kernel/sched/core.c:6557
       preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
       irqentry_exit+0x53/0x80 kernel/entry/common.c:439
       asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
       exit_to_user_mode_loop+0x3d/0x100 kernel/entry/common.c:164
       exit_to_user_mode_prepare+0xb1/0x140 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.4.2804/12574:
 #0: ffff8880b8f3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline]
 #1: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2325
 #2: ffffffff8d20a5a0 (console_lock){+.+.}-{0:0}, at: _printk+0xd1/0x111 kernel/printk/printk.c:2328

stack backtrace:
CPU: 1 PID: 12574 Comm: syz.4.2804 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 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+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 console_lock_spinning_enable kernel/printk/printk.c:1818 [inline]
 console_emit_next_record+0x76c/0xc30 kernel/printk/printk.c:2774
 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906
 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303
 _printk+0xd1/0x111 kernel/printk/printk.c:2328
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail_ex+0x387/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6c/0x130 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+0xe4/0x180 kernel/trace/bpf_trace.c:306
 bpf_prog_c1796171ffc7efef+0x35/0x37
 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
 bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2128/0x4570 kernel/sched/core.c:6557
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:exit_to_user_mode_loop+0x3d/0x100 kernel/entry/common.c:164
Code: 49 89 fe eb 1c e8 b3 97 3a 09 65 48 8b 05 eb 0c 8c 7e 48 8b 18 f7 c3 0e 30 02 00 0f 84 be 00 00 00 e8 37 f5 1a 00 fb f6 c3 08 <74> 05 e8 2c 39 43 09 f7 c3 00 10 00 00 74 08 4c 89 f7 e8 1c f3 3e
RSP: 0000:ffffc90004fd7f10 EFLAGS: 00000202
RAX: 5e6161e96a0a4c00 RBX: 0000000000000008 RCX: ffffffff973bd103
RDX: dffffc0000000000 RSI: ffffffff8b0c1d40 RDI: ffffffff8b5f6d80
RBP: 0000000000000000 R08: ffffffff901cb040 R09: ffffffff901cb048
R10: ffffffff901cb058 R11: ffffffff901cb050 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90004fd7f58 R15: ffff888030f50000
 exit_to_user_mode_prepare+0xb1/0x140 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: 0033:0x7f450c7b4f99
Code: 1d 13 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 e7 02 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 <8b> 90 08 03 00 00 48 8d b8 08 03 00 00 89 d1 89 d0 83 e1 fd f0 0f
RSP: 002b:00007f450d58f028 EFLAGS: 00000246
RAX: 00007f450d58f6c0 RBX: 0000000000000006 RCX: 00007f450c78bc1f
RDX: 0000000000000001 RSI: 00007f450d58f090 RDI: 0000000000000000
RBP: 00007f450d58f090 R08: 0000000000000000 R09: 00007f450d58edf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f450c9a5fa0 R15: 00007fff4e2f8748
 </TASK>
CPU: 1 PID: 12574 Comm: syz.4.2804 Not tainted 6.1.129-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail_ex+0x3a6/0x4d0 lib/fault-inject.c:147
 strncpy_from_user+0x32/0x360 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x6c/0x130 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+0xe4/0x180 kernel/trace/bpf_trace.c:306
 bpf_prog_c1796171ffc7efef+0x35/0x37
 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [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:2284 [inline]
 bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325
 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2128/0x4570 kernel/sched/core.c:6557
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:exit_to_user_mode_loop+0x3d/0x100 kernel/entry/common.c:164
Code: 49 89 fe eb 1c e8 b3 97 3a 09 65 48 8b 05 eb 0c 8c 7e 48 8b 18 f7 c3 0e 30 02 00 0f 84 be 00 00 00 e8 37 f5 1a 00 fb f6 c3 08 <74> 05 e8 2c 39 43 09 f7 c3 00 10 00 00 74 08 4c 89 f7 e8 1c f3 3e
RSP: 0000:ffffc90004fd7f10 EFLAGS: 00000202
RAX: 5e6161e96a0a4c00 RBX: 0000000000000008 RCX: ffffffff973bd103
RDX: dffffc0000000000 RSI: ffffffff8b0c1d40 RDI: ffffffff8b5f6d80
RBP: 0000000000000000 R08: ffffffff901cb040 R09: ffffffff901cb048
R10: ffffffff901cb058 R11: ffffffff901cb050 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc90004fd7f58 R15: ffff888030f50000
 exit_to_user_mode_prepare+0xb1/0x140 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: 0033:0x7f450c7b4f99
Code: 1d 13 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 e7 02 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 <8b> 90 08 03 00 00 48 8d b8 08 03 00 00 89 d1 89 d0 83 e1 fd f0 0f
RSP: 002b:00007f450d58f028 EFLAGS: 00000246
RAX: 00007f450d58f6c0 RBX: 0000000000000006 RCX: 00007f450c78bc1f
RDX: 0000000000000001 RSI: 00007f450d58f090 RDI: 0000000000000000
RBP: 00007f450d58f090 R08: 0000000000000000 R09: 00007f450d58edf7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f450c9a5fa0 R15: 00007fff4e2f8748
 </TASK>
----------------
Code disassembly (best guess):
   0:	49 89 fe             	mov    %rdi,%r14
   3:	eb 1c                	jmp    0x21
   5:	e8 b3 97 3a 09       	call   0x93a97bd
   a:	65 48 8b 05 eb 0c 8c 	mov    %gs:0x7e8c0ceb(%rip),%rax        # 0x7e8c0cfd
  11:	7e
  12:	48 8b 18             	mov    (%rax),%rbx
  15:	f7 c3 0e 30 02 00    	test   $0x2300e,%ebx
  1b:	0f 84 be 00 00 00    	je     0xdf
  21:	e8 37 f5 1a 00       	call   0x1af55d
  26:	fb                   	sti
  27:	f6 c3 08             	test   $0x8,%bl
* 2a:	74 05                	je     0x31 <-- trapping instruction
  2c:	e8 2c 39 43 09       	call   0x943395d
  31:	f7 c3 00 10 00 00    	test   $0x1000,%ebx
  37:	74 08                	je     0x41
  39:	4c 89 f7             	mov    %r14,%rdi
  3c:	e8                   	.byte 0xe8
  3d:	1c f3                	sbb    $0xf3,%al
  3f:	3e                   	ds