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.5.2940/15382 is trying to acquire lock:
ffffffff8df31620 (console_owner){-.-.}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
ffffffff8df31620 (console_owner){-.-.}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
ffffffff8df31620 (console_owner){-.-.}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
ffffffff8df31620 (console_owner){-.-.}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176

but task is already holding lock:
ffff88801a0c0018 (&pool->lock){-.-.}-{2:2}, at: __queue_work+0x809/0xfb0 kernel/workqueue.c:-1

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&pool->lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __queue_work+0x809/0xfb0 kernel/workqueue.c:-1
       queue_work_on+0x181/0x270 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:669 [inline]
       rpm_suspend+0xe54/0x1720 drivers/base/power/runtime.c:688
       __pm_runtime_idle+0x12f/0x1a0 drivers/base/power/runtime.c:1129
       pm_runtime_put include/linux/pm_runtime.h:563 [inline]
       __device_attach+0x342/0x400 drivers/base/dd.c:1049
       bus_probe_device+0x185/0x260 drivers/base/bus.c:537
       device_add+0x7b6/0xb50 drivers/base/core.c:3689
       serial_base_port_add+0x2e3/0x410 drivers/tty/serial/serial_base_bus.c:183
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3284 [inline]
       serial_core_register_port+0x369/0x2800 drivers/tty/serial/serial_core.c:3323
       serial8250_register_8250_port+0x16db/0x2080 drivers/tty/serial/8250/8250_core.c:818
       serial_pnp_probe+0x527/0x790 drivers/tty/serial/8250/8250_pnp.c:480
       pnp_device_probe+0x30b/0x4c0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x26d/0x9e0 drivers/base/dd.c:659
       __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801
       driver_probe_device+0x4f/0x430 drivers/base/dd.c:831
       __driver_attach+0x452/0x700 drivers/base/dd.c:1217
       bus_for_each_dev+0x233/0x2b0 drivers/base/bus.c:370
       bus_add_driver+0x345/0x640 drivers/base/bus.c:678
       driver_register+0x23a/0x320 drivers/base/driver.c:249
       serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:320
       do_one_initcall+0x236/0x820 init/main.c:1283
       do_initcall_level+0x104/0x190 init/main.c:1345
       do_initcalls+0x59/0xa0 init/main.c:1361
       kernel_init_freeable+0x334/0x4b0 init/main.c:1593
       kernel_init+0x1d/0x1d0 init/main.c:1483
       ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&dev->power.lock){-.-.}-{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
       __pm_runtime_resume+0x10f/0x180 drivers/base/power/runtime.c:1196
       pm_runtime_get include/linux/pm_runtime.h:494 [inline]
       __uart_start+0x171/0x460 drivers/tty/serial/serial_core.c:149
       uart_write+0xdc/0x130 drivers/tty/serial/serial_core.c:633
       process_output_block drivers/tty/n_tty.c:561 [inline]
       n_tty_write+0xd27/0x1200 drivers/tty/n_tty.c:2377
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write+0x559/0xa20 drivers/tty/tty_io.c:1081
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x5c9/0xb30 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/0xfa0 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: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_lock_spinning_enable kernel/printk/printk.c:1897 [inline]
       console_emit_next_record kernel/printk/printk.c:3105 [inline]
       console_flush_all+0x69c/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
       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_a3b97ca3d235027a+0x41/0x47
       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_run1+0x27f/0x4b0 kernel/trace/bpf_trace.c:2115
       __bpf_trace_workqueue_activate_work+0xae/0x100 include/trace/events/workqueue.h:59
       __do_trace_workqueue_activate_work include/trace/events/workqueue.h:59 [inline]
       trace_workqueue_activate_work+0x170/0x1d0 include/trace/events/workqueue.h:59
       __queue_work+0xcc2/0xfb0 kernel/workqueue.c:2340
       queue_work_on+0x181/0x270 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:669 [inline]
       call_usermodehelper_exec+0x295/0x4b0 kernel/umh.c:433
       call_modprobe kernel/module/kmod.c:102 [inline]
       __request_module+0x3c0/0x5e0 kernel/module/kmod.c:172
       rtnl_newlink+0x65d/0x1c80 net/core/rtnetlink.c:4004
       rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
       netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
       netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
       netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
       netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
       sock_sendmsg_nosec net/socket.c:727 [inline]
       __sock_sendmsg+0x21c/0x270 net/socket.c:742
       ____sys_sendmsg+0x505/0x830 net/socket.c:2630
       ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
       __sys_sendmsg net/socket.c:2716 [inline]
       __do_sys_sendmsg net/socket.c:2721 [inline]
       __se_sys_sendmsg net/socket.c:2719 [inline]
       __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
       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 --> &dev->power.lock --> &pool->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&pool->lock);
                               lock(&dev->power.lock);
                               lock(&pool->lock);
  lock(console_owner);

 *** DEADLOCK ***

5 locks held by syz.5.2940/15382:
 #0: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: __queue_work+0x102/0xfb0 kernel/workqueue.c:2261
 #1: ffff88801a0c0018 (&pool->lock){-.-.}-{2:2}, at: __queue_work+0x809/0xfb0 kernel/workqueue.c:-1
 #2: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #2: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #2: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2074 [inline]
 #2: ffffffff8df3d6a0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run1+0x181/0x4b0 kernel/trace/bpf_trace.c:2115
 #3: ffffffff8df31680 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x120 kernel/printk/printk.c:2448
 #4: ffffffff8de18f50 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #4: ffffffff8de18f50 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:335 [inline]
 #4: ffffffff8de18f50 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:289 [inline]
 #4: ffffffff8de18f50 (console_srcu){....}-{0:0}, at: console_flush_all+0x13a/0xb10 kernel/printk/printk.c:3176

stack backtrace:
CPU: 0 UID: 0 PID: 15382 Comm: syz.5.2940 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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_lock_spinning_enable kernel/printk/printk.c:1897 [inline]
 console_emit_next_record kernel/printk/printk.c:3105 [inline]
 console_flush_all+0x69c/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
 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_a3b97ca3d235027a+0x41/0x47
 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_run1+0x27f/0x4b0 kernel/trace/bpf_trace.c:2115
 __bpf_trace_workqueue_activate_work+0xae/0x100 include/trace/events/workqueue.h:59
 __do_trace_workqueue_activate_work include/trace/events/workqueue.h:59 [inline]
 trace_workqueue_activate_work+0x170/0x1d0 include/trace/events/workqueue.h:59
 __queue_work+0xcc2/0xfb0 kernel/workqueue.c:2340
 queue_work_on+0x181/0x270 kernel/workqueue.c:2392
 queue_work include/linux/workqueue.h:669 [inline]
 call_usermodehelper_exec+0x295/0x4b0 kernel/umh.c:433
 call_modprobe kernel/module/kmod.c:102 [inline]
 __request_module+0x3c0/0x5e0 kernel/module/kmod.c:172
 rtnl_newlink+0x65d/0x1c80 net/core/rtnetlink.c:4004
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x830 net/socket.c:2630
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 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: 0033:0x7f16fc58f6c9
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:00007f16fd458038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f16fc7e5fa0 RCX: 00007f16fc58f6c9
RDX: 0000000000004040 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f16fd458090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f16fc7e6038 R14: 00007f16fc7e5fa0 R15: 00007ffc9461acd8
 </TASK>
CPU: 0 UID: 0 PID: 15382 Comm: syz.5.2940 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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_a3b97ca3d235027a+0x41/0x47
 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_run1+0x27f/0x4b0 kernel/trace/bpf_trace.c:2115
 __bpf_trace_workqueue_activate_work+0xae/0x100 include/trace/events/workqueue.h:59
 __do_trace_workqueue_activate_work include/trace/events/workqueue.h:59 [inline]
 trace_workqueue_activate_work+0x170/0x1d0 include/trace/events/workqueue.h:59
 __queue_work+0xcc2/0xfb0 kernel/workqueue.c:2340
 queue_work_on+0x181/0x270 kernel/workqueue.c:2392
 queue_work include/linux/workqueue.h:669 [inline]
 call_usermodehelper_exec+0x295/0x4b0 kernel/umh.c:433
 call_modprobe kernel/module/kmod.c:102 [inline]
 __request_module+0x3c0/0x5e0 kernel/module/kmod.c:172
 rtnl_newlink+0x65d/0x1c80 net/core/rtnetlink.c:4004
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x830 net/socket.c:2630
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 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: 0033:0x7f16fc58f6c9
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:00007f16fd458038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f16fc7e5fa0 RCX: 00007f16fc58f6c9
RDX: 0000000000004040 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007f16fd458090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f16fc7e6038 R14: 00007f16fc7e5fa0 R15: 00007ffc9461acd8
 </TASK>