FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.6.102-syzkaller #0 Not tainted
------------------------------------------------------
syz.7.1939/12210 is trying to acquire lock:
ffffffff8cd23e20 (console_owner){-...}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline]
ffffffff8cd23e20 (console_owner){-...}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline]
ffffffff8cd23e20 (console_owner){-...}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline]
ffffffff8cd23e20 (console_owner){-...}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992

but task is already holding lock:
ffff8880b8e3c458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
       raw_spin_rq_lock kernel/sched/sched.h:1372 [inline]
       rq_lock kernel/sched/sched.h:1681 [inline]
       task_fork_fair+0x62/0x1f0 kernel/sched/fair.c:12662
       sched_cgroup_fork+0x333/0x3c0 kernel/sched/core.c:4816
       copy_process+0x21e4/0x3d70 kernel/fork.c:2614
       kernel_clone+0x21b/0x840 kernel/fork.c:2914
       user_mode_thread+0xde/0x130 kernel/fork.c:2992
       rest_init+0x27/0x300 init/main.c:697
       arch_call_rest_init+0xe/0x10 init/main.c:829
       start_kernel+0x459/0x4e0 init/main.c:1074
       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

-> #4 (&p->pi_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
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:522 [inline]
       try_to_wake_up+0x60/0x1140 kernel/sched/core.c:4232
       kick_pool+0x320/0x420 kernel/workqueue.c:1146
       create_worker+0x5c0/0x7b0 kernel/workqueue.c:2218
       workqueue_init+0x306/0x670 kernel/workqueue.c:6736
       kernel_init_freeable+0x3a0/0x570 init/main.c:1538
       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

-> #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:462 [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:410 [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:3434
       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_c1796171ffc7efef+0x3d/0x3f
       bpf_dispatcher_nop_func include/linux/bpf.h:1213 [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_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363
       __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222
       __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222
       trace_sched_switch include/trace/events/sched.h:222 [inline]
       __schedule+0x2197/0x44d0 kernel/sched/core.c:6696
       schedule+0xbd/0x170 kernel/sched/core.c:6773
       schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
       __mutex_lock_common kernel/locking/mutex.c:679 [inline]
       __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
       rtnl_lock net/core/rtnetlink.c:78 [inline]
       rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
       netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2555
       netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
       netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1356
       netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1904
       sock_sendmsg_nosec net/socket.c:730 [inline]
       __sock_sendmsg net/socket.c:745 [inline]
       ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
       ___sys_sendmsg+0x220/0x290 net/socket.c:2649
       __sys_sendmsg net/socket.c:2678 [inline]
       __do_sys_sendmsg net/socket.c:2687 [inline]
       __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
       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 --> &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 ***

5 locks held by syz.7.1939/12210:
 #0: ffffffff8dfbba48 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:78 [inline]
 #0: ffffffff8dfbba48 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
 #1: ffff8880b8e3c458 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558
 #2: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #2: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #2: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2321 [inline]
 #2: ffffffff8cd2fbe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0xfd/0x420 kernel/trace/bpf_trace.c:2363
 #3: ffffffff8cd23f00 (console_lock){+.+.}-{0:0}, at: _printk+0xd0/0x110 kernel/printk/printk.c:2366
 #4: ffffffff8cc0b710 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:339 [inline]
 #4: ffffffff8cc0b710 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline]
 #4: ffffffff8cc0b710 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:292 [inline]
 #4: ffffffff8cc0b710 (console_srcu){....}-{0:0}, at: console_flush_all+0x10f/0xd00 kernel/printk/printk.c:2992

stack backtrace:
CPU: 0 PID: 12210 Comm: syz.7.1939 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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_c1796171ffc7efef+0x3d/0x3f
 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [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_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363
 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222
 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2197/0x44d0 kernel/sched/core.c:6696
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 rtnl_lock net/core/rtnetlink.c:78 [inline]
 rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2555
 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1356
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1904
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 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: 0033:0x7fd44ad8ebe9
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:00007fd44bbe6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd44afb5fa0 RCX: 00007fd44ad8ebe9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000005
RBP: 00007fd44bbe6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd44afb6038 R14: 00007fd44afb5fa0 R15: 00007ffd5af3a5f8
 </TASK>
CPU: 0 PID: 12210 Comm: syz.7.1939 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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
 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_c1796171ffc7efef+0x3d/0x3f
 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [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_run4+0x1f9/0x420 kernel/trace/bpf_trace.c:2363
 __bpf_trace_sched_switch+0x17b/0x1e0 include/trace/events/sched.h:222
 __traceiter_sched_switch+0x93/0xc0 include/trace/events/sched.h:222
 trace_sched_switch include/trace/events/sched.h:222 [inline]
 __schedule+0x2197/0x44d0 kernel/sched/core.c:6696
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 rtnl_lock net/core/rtnetlink.c:78 [inline]
 rtnetlink_rcv_msg+0x76f/0xf10 net/core/rtnetlink.c:6472
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2555
 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
 netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1356
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1904
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 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: 0033:0x7fd44ad8ebe9
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:00007fd44bbe6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fd44afb5fa0 RCX: 00007fd44ad8ebe9
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000005
RBP: 00007fd44bbe6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd44afb6038 R14: 00007fd44afb5fa0 R15: 00007ffd5af3a5f8
 </TASK>