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.8.5509/27861 is trying to acquire lock:
ffffffff8df315a0 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2021 [inline]
ffffffff8df315a0 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x2ee/0x590 kernel/printk/printk.c:2422

but task is already holding lock:
ffff8880b883a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638

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:5868
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
       raw_spin_rq_lock kernel/sched/sched.h:1547 [inline]
       task_rq_lock+0xbc/0x470 kernel/sched/core.c:738
       cgroup_move_task+0x92/0x2a0 kernel/sched/psi.c:1170
       css_set_move_task+0x658/0x9e0 kernel/cgroup/cgroup.c:951
       cgroup_post_fork+0x1ef/0x790 kernel/cgroup/cgroup.c:6913
       copy_process+0x3862/0x3c00 kernel/fork.c:2425
       kernel_clone+0x21e/0x840 kernel/fork.c:2609
       user_mode_thread+0xdd/0x140 kernel/fork.c:2685
       rest_init+0x23/0x300 init/main.c:722
       start_kernel+0x3ae/0x410 init/main.c:1111
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #3 (&p->pi_lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __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+0x67/0x12b0 kernel/sched/core.c:4181
       __wake_up_common kernel/sched/wait.c:108 [inline]
       __wake_up_common_lock+0x137/0x1f0 kernel/sched/wait.c:125
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203
       handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
       handle_edge_irq+0x23b/0xa10 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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       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:767
       default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e7/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
       common_startup_64+0x13e/0x147

-> #2 (&tty->write_wait){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __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:124
       tty_port_default_wakeup+0xfb/0x170 drivers/tty/tty_port.c:67
       serial8250_tx_chars+0x72e/0x970 drivers/tty/serial/8250/8250_port.c:1719
       serial8250_handle_irq+0x633/0xbb0 drivers/tty/serial/8250/8250_port.c:1827
       serial8250_default_handle_irq+0xbf/0x200 drivers/tty/serial/8250/8250_port.c:1846
       serial8250_interrupt+0x8d/0x180 drivers/tty/serial/8250/8250_core.c:82
       __handle_irq_event_percpu+0x295/0xab0 kernel/irq/handle.c:203
       handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
       handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:257
       handle_edge_irq+0x23b/0xa10 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:-1 [inline]
       __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:325
       common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:318
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
       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:767
       default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
       cpuidle_idle_call kernel/sched/idle.c:190 [inline]
       do_idle+0x1e7/0x510 kernel/sched/idle.c:330
       cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
       start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
       common_startup_64+0x13e/0x147

-> #1 (&port_lock_key){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __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:717 [inline]
       serial8250_console_write+0x17e/0x1ba0 drivers/tty/serial/8250/8250_port.c:3301
       console_emit_next_record kernel/printk/printk.c:3111 [inline]
       console_flush_all+0x6f3/0xb10 kernel/printk/printk.c:3199
       __console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
       console_unlock+0xbb/0x190 kernel/printk/printk.c:3298
       vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
       _printk+0xcf/0x120 kernel/printk/printk.c:2448
       register_console+0xa8b/0xf90 kernel/printk/printk.c:4099
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:511
       console_init+0x10e/0x430 kernel/printk/printk.c:4298
       start_kernel+0x254/0x410 init/main.c:1048
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x147

-> #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+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       console_trylock_spinning kernel/printk/printk.c:2021 [inline]
       vprintk_emit+0x30a/0x590 kernel/printk/printk.c:2422
       _printk+0xcf/0x120 kernel/printk/printk.c:2448
       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:192
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
       ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:223 [inline]
       bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220
       bpf_prog_c762caf419d1c004+0x3e/0x44
       bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
       __bpf_prog_run include/linux/filter.h:721 [inline]
       bpf_prog_run include/linux/filter.h:728 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
       bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
       __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+0x238f/0x4cc0 kernel/sched/core.c:6926
       __schedule_loop kernel/sched/core.c:7011 [inline]
       schedule+0x165/0x360 kernel/sched/core.c:7026
       fuse_dev_do_read+0x73c/0x1240 fs/fuse/dev.c:1441
       fuse_dev_read+0x14c/0x1d0 fs/fuse/dev.c:1585
       new_sync_read fs/read_write.c:491 [inline]
       vfs_read+0x55a/0xa30 fs/read_write.c:572
       ksys_read+0x145/0x250 fs/read_write.c:715
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
       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 ***

2 locks held by syz.8.5509/27861:
 #0: ffff8880b883a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638
 #1: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #1: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #1: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #1: ffffffff8df3d620 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run4+0x19c/0x4a0 kernel/trace/bpf_trace.c:2118

stack backtrace:
CPU: 0 UID: 0 PID: 27861 Comm: syz.8.5509 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 console_trylock_spinning kernel/printk/printk.c:2021 [inline]
 vprintk_emit+0x30a/0x590 kernel/printk/printk.c:2422
 _printk+0xcf/0x120 kernel/printk/printk.c:2448
 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:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:223 [inline]
 bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220
 bpf_prog_c762caf419d1c004+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
 __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+0x238f/0x4cc0 kernel/sched/core.c:6926
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 fuse_dev_do_read+0x73c/0x1240 fs/fuse/dev.c:1441
 fuse_dev_read+0x14c/0x1d0 fs/fuse/dev.c:1585
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x55a/0xa30 fs/read_write.c:572
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f209978d9dc
Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 93 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 ef 93 02 00 48
RSP: 002b:00007f209a6dffb0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000200000006380 RCX: 00007f209978d9dc
RDX: 0000000000002000 RSI: 0000200000006380 RDI: 0000000000000004
RBP: 00007f209a6e0090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000004
R13: 0000200000000dc0 R14: 00007f20999e5fa0 R15: 00007fff24624088
 </TASK>
CPU: 0 UID: 0 PID: 27861 Comm: syz.8.5509 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:192
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:214 [inline]
 ____bpf_probe_read_user_str kernel/trace/bpf_trace.c:223 [inline]
 bpf_probe_read_user_str+0x2a/0x70 kernel/trace/bpf_trace.c:220
 bpf_prog_c762caf419d1c004+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1350 [inline]
 __bpf_prog_run include/linux/filter.h:721 [inline]
 bpf_prog_run include/linux/filter.h:728 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2075 [inline]
 bpf_trace_run4+0x28e/0x4a0 kernel/trace/bpf_trace.c:2118
 __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+0x238f/0x4cc0 kernel/sched/core.c:6926
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 fuse_dev_do_read+0x73c/0x1240 fs/fuse/dev.c:1441
 fuse_dev_read+0x14c/0x1d0 fs/fuse/dev.c:1585
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x55a/0xa30 fs/read_write.c:572
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f209978d9dc
Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 93 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 ef 93 02 00 48
RSP: 002b:00007f209a6dffb0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000200000006380 RCX: 00007f209978d9dc
RDX: 0000000000002000 RSI: 0000200000006380 RDI: 0000000000000004
RBP: 00007f209a6e0090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000004
R13: 0000200000000dc0 R14: 00007f20999e5fa0 R15: 00007fff24624088
 </TASK>