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-g99fe8af069a9 #0 Not tainted
------------------------------------------------------
syz.2.236/6935 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:6759
       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
       __sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:233
       do_dentry_open+0x1094/0x1970 fs/open.c:975
       vfs_open+0x3b/0x340 fs/open.c:1094
       do_open fs/namei.c:3887 [inline]
       path_openat+0x2ee5/0x3830 fs/namei.c:4046
       do_filp_open+0x1fa/0x410 fs/namei.c:4073
       do_sys_openat2+0x121/0x1c0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_openat fs/open.c:1468 [inline]
       __se_sys_openat fs/open.c:1463 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1463
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #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
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
       _raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
       spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
       uart_port_unlock_irqrestore include/linux/serial_core.h:786 [inline]
       uart_write+0x3ba/0xa40 drivers/tty/serial/serial_core.c:636
       process_output_block drivers/tty/n_tty.c:561 [inline]
       n_tty_write+0xd35/0x11d0 drivers/tty/n_tty.c:2377
       iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
       file_tty_write+0x503/0x990 drivers/tty/tty_io.c:1090
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x54b/0xa90 fs/read_write.c:686
       ksys_write+0x145/0x250 fs/read_write.c:738
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #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_bc7c5c6b9645592f+0x3e/0x44
       bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
       __bpf_prog_run include/linux/filter.h:709 [inline]
       bpf_prog_run include/linux/filter.h:725 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline]
       bpf_trace_run4+0x3f2/0x4a0 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
       schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
       __mutex_lock_common kernel/locking/mutex.c:679 [inline]
       __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
       dev_ethtool+0x1d0/0x1990 net/ethtool/ioctl.c:3489
       dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:758
       sock_do_ioctl+0x22c/0x300 net/socket.c:1204
       sock_ioctl+0x576/0x790 net/socket.c:1311
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 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 ***

3 locks held by syz.2.236/6935:
 #0: ffffffff8f50f6c8 (rtnl_mutex){+.+.}-{4:4}, at: dev_ethtool+0x1d0/0x1990 net/ethtool/ioctl.c:3489
 #1: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
 #2: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #2: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2257 [inline]
 #2: 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: 6935 Comm: syz.2.236 Not tainted 6.15.0-syzkaller-g99fe8af069a9 #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_bc7c5c6b9645592f+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:709 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline]
 bpf_trace_run4+0x3f2/0x4a0 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
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 dev_ethtool+0x1d0/0x1990 net/ethtool/ioctl.c:3489
 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:758
 sock_do_ioctl+0x22c/0x300 net/socket.c:1204
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0382f8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0383d3f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f03831b5fa0 RCX: 00007f0382f8e929
RDX: 0000200000000080 RSI: 0000000000008946 RDI: 000000000000002e
RBP: 00007f0383d3f090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f03831b5fa0 R15: 00007ffd31bc62f8
 </TASK>
CPU: 0 UID: 0 PID: 6935 Comm: syz.2.236 Not tainted 6.15.0-syzkaller-g99fe8af069a9 #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_bc7c5c6b9645592f+0x3e/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline]
 __bpf_prog_run include/linux/filter.h:709 [inline]
 bpf_prog_run include/linux/filter.h:725 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline]
 bpf_trace_run4+0x3f2/0x4a0 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
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 dev_ethtool+0x1d0/0x1990 net/ethtool/ioctl.c:3489
 dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:758
 sock_do_ioctl+0x22c/0x300 net/socket.c:1204
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0382f8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0383d3f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f03831b5fa0 RCX: 00007f0382f8e929
RDX: 0000200000000080 RSI: 0000000000008946 RDI: 000000000000002e
RBP: 00007f0383d3f090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f03831b5fa0 R15: 00007ffd31bc62f8
 </TASK>