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.2.297/6754 is trying to acquire lock:
ffffffff8cd24080 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline]
ffffffff8cd24080 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline]
ffffffff8cd24080 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline]
ffffffff8cd24080 (console_owner){-...}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992

but task is already holding lock:
ffff8880b8e297d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&base->lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
       lock_timer_base+0x123/0x270 kernel/time/timer.c:999
       __mod_timer+0xf9/0xdb0 kernel/time/timer.c:1080
       worker_enter_idle+0x354/0x500 kernel/workqueue.c:945
       worker_thread+0xba2/0xfc0 kernel/workqueue.c:2804
       kthread+0x2fa/0x390 kernel/kthread.c:388
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

-> #3 (&pool->lock){-.-.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __queue_work+0x69f/0x1020 kernel/workqueue.c:1764
       queue_work_on+0x121/0x1e0 kernel/workqueue.c:1835
       queue_work include/linux/workqueue.h:562 [inline]
       rpm_suspend+0x10bc/0x1a90 drivers/base/power/runtime.c:660
       __pm_runtime_idle+0x12f/0x1a0 drivers/base/power/runtime.c:1102
       pm_runtime_put include/linux/pm_runtime.h:450 [inline]
       __device_attach+0x33f/0x400 drivers/base/dd.c:1048
       bus_probe_device+0x180/0x260 drivers/base/bus.c:534
       device_add+0x85b/0xc20 drivers/base/core.c:3683
       serial_base_port_add+0x2f2/0x420 drivers/tty/serial/serial_base_bus.c:178
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3382 [inline]
       serial_core_register_port+0x36d/0x2320 drivers/tty/serial/serial_core.c:3423
       serial8250_register_8250_port+0x15ec/0x1f10 drivers/tty/serial/8250/8250_core.c:1142
       serial_pnp_probe+0x549/0x730 drivers/tty/serial/8250/8250_pnp.c:478
       pnp_device_probe+0x305/0x4b0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x25b/0xb40 drivers/base/dd.c:658
       __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800
       driver_probe_device+0x4f/0x420 drivers/base/dd.c:830
       __driver_attach+0x44e/0x6f0 drivers/base/dd.c:1216
       bus_for_each_dev+0x22d/0x2a0 drivers/base/bus.c:370
       bus_add_driver+0x340/0x640 drivers/base/bus.c:675
       driver_register+0x23a/0x310 drivers/base/driver.c:246
       serial8250_init+0x9a/0x170 drivers/tty/serial/8250/8250_core.c:1243
       do_one_initcall+0x1fd/0x750 init/main.c:1238
       do_initcall_level+0x137/0x1f0 init/main.c:1300
       do_initcalls+0x69/0xd0 init/main.c:1316
       kernel_init_freeable+0x3d2/0x570 init/main.c:1553
       kernel_init+0x1d/0x1c0 init/main.c:1443
       ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
       ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

-> #2 (&dev->power.lock){-...}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
       __pm_runtime_resume+0x10f/0x170 drivers/base/power/runtime.c:1169
       pm_runtime_get include/linux/pm_runtime.h:398 [inline]
       __uart_start+0x171/0x3e0 drivers/tty/serial/serial_core.c:148
       uart_write+0x449/0x5d0 drivers/tty/serial/serial_core.c:633
       process_output_block drivers/tty/n_tty.c:580 [inline]
       n_tty_write+0xd27/0x11d0 drivers/tty/n_tty.c:2395
       iterate_tty_write drivers/tty/tty_io.c:1017 [inline]
       file_tty_write+0x54b/0x980 drivers/tty/tty_io.c:1088
       call_write_iter include/linux/fs.h:2018 [inline]
       new_sync_write fs/read_write.c:491 [inline]
       vfs_write+0x43b/0x940 fs/read_write.c:584
       ksys_write+0x147/0x250 fs/read_write.c:637
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&port_lock_key){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa8/0xf0 kernel/locking/spinlock.c:162
       serial8250_console_write+0x16d/0x17a0 drivers/tty/serial/8250/8250_port.c:3433
       console_emit_next_record kernel/printk/printk.c:2944 [inline]
       console_flush_all+0x6cd/0xd00 kernel/printk/printk.c:3000
       console_unlock+0xae/0x340 kernel/printk/printk.c:3069
       vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
       _printk+0xd0/0x110 kernel/printk/printk.c:2366
       register_console+0x91b/0xe60 kernel/printk/printk.c:3583
       univ8250_console_init+0x45/0x50 drivers/tty/serial/8250/8250_core.c:717
       console_init+0x17b/0x5e0 kernel/printk/printk.c:3726
       start_kernel+0x2c0/0x4e0 init/main.c:1010
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
       copy_bootdata+0x0/0xe0 arch/x86/kernel/head64.c:536
       secondary_startup_64_no_verify+0x179/0x17b

-> #0 (console_owner){-...}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
       lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
       console_lock_spinning_enable kernel/printk/printk.c:1871 [inline]
       console_emit_next_record kernel/printk/printk.c:2938 [inline]
       console_flush_all+0x693/0xd00 kernel/printk/printk.c:3000
       console_unlock+0xae/0x340 kernel/printk/printk.c:3069
       vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
       _printk+0xd0/0x110 kernel/printk/printk.c:2366
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail_ex+0x37e/0x4d0 lib/fault-inject.c:153
       strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:212 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:307 [inline]
       bpf_probe_read_compat_str+0xe1/0x170 kernel/trace/bpf_trace.c:303
       bpf_prog_cd413097421e9883+0x48/0x4f
       bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline]
       __bpf_prog_run include/linux/filter.h:612 [inline]
       bpf_prog_run include/linux/filter.h:619 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
       bpf_trace_run3+0x1e7/0x400 kernel/trace/bpf_trace.c:2362
       __bpf_trace_timer_start+0x14a/0x1b0 include/trace/events/timer.h:53
       trace_timer_start include/trace/events/timer.h:53 [inline]
       enqueue_timer+0x398/0x530 kernel/time/timer.c:609
       internal_add_timer kernel/time/timer.c:634 [inline]
       __mod_timer+0x977/0xdb0 kernel/time/timer.c:1131
       sk_reset_timer+0x23/0xc0 net/core/sock.c:3412
       tipc_sk_finish_conn+0x154/0x7e0 net/tipc/socket.c:1676
       tipc_socketpair+0x254/0x470 net/tipc/socket.c:3353
       __sys_socketpair+0x2b0/0x550 net/socket.c:1795
       __do_sys_socketpair net/socket.c:1831 [inline]
       __se_sys_socketpair net/socket.c:1828 [inline]
       __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1828
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 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 --> &pool->lock --> &base->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&base->lock);
                               lock(&pool->lock);
                               lock(&base->lock);
  lock(console_owner);

 *** DEADLOCK ***

4 locks held by syz.2.297/6754:
 #0: ffff8880b8e297d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
 #1: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #1: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #1: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline]
 #1: ffffffff8cd2fe20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0xf4/0x400 kernel/trace/bpf_trace.c:2362
 #2: ffffffff8cd24160 (console_lock){+.+.}-{0:0}, at: _printk+0xd0/0x110 kernel/printk/printk.c:2366
 #3: ffffffff8cc0b970 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline]
 #3: ffffffff8cc0b970 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline]
 #3: ffffffff8cc0b970 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline]
 #3: ffffffff8cc0b970 (console_srcu){....}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992

stack backtrace:
CPU: 0 PID: 6754 Comm: syz.2.297 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 console_lock_spinning_enable kernel/printk/printk.c:1871 [inline]
 console_emit_next_record kernel/printk/printk.c:2938 [inline]
 console_flush_all+0x693/0xd00 kernel/printk/printk.c:3000
 console_unlock+0xae/0x340 kernel/printk/printk.c:3069
 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341
 _printk+0xd0/0x110 kernel/printk/printk.c:2366
 fail_dump lib/fault-inject.c:45 [inline]
 should_fail_ex+0x37e/0x4d0 lib/fault-inject.c:153
 strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:212 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:307 [inline]
 bpf_probe_read_compat_str+0xe1/0x170 kernel/trace/bpf_trace.c:303
 bpf_prog_cd413097421e9883+0x48/0x4f
 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline]
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
 bpf_trace_run3+0x1e7/0x400 kernel/trace/bpf_trace.c:2362
 __bpf_trace_timer_start+0x14a/0x1b0 include/trace/events/timer.h:53
 trace_timer_start include/trace/events/timer.h:53 [inline]
 enqueue_timer+0x398/0x530 kernel/time/timer.c:609
 internal_add_timer kernel/time/timer.c:634 [inline]
 __mod_timer+0x977/0xdb0 kernel/time/timer.c:1131
 sk_reset_timer+0x23/0xc0 net/core/sock.c:3412
 tipc_sk_finish_conn+0x154/0x7e0 net/tipc/socket.c:1676
 tipc_socketpair+0x254/0x470 net/tipc/socket.c:3353
 __sys_socketpair+0x2b0/0x550 net/socket.c:1795
 __do_sys_socketpair net/socket.c:1831 [inline]
 __se_sys_socketpair net/socket.c:1828 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1828
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f53a658eba9
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:00007f53a7478038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f53a67d5fa0 RCX: 00007f53a658eba9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 000000000000001e
RBP: 00007f53a7478090 R08: 0000000000000000 R09: 0000000000000000
R10: 00002000000010c0 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f53a67d6038 R14: 00007f53a67d5fa0 R15: 00007ffdb8cfda08
 </TASK>
CPU: 0 PID: 6754 Comm: syz.2.297 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail_ex+0x39d/0x4d0 lib/fault-inject.c:153
 strncpy_from_user+0x36/0x2e0 lib/strncpy_from_user.c:118