[   10.074626][  T251] 
[   10.074825][  T251] ============================================
[   10.075052][  T251] WARNING: possible recursive locking detected
[   10.075279][  T251] 6.13.0-rc5-virtme #1 Not tainted
[   10.075462][  T251] --------------------------------------------
[   10.075680][  T251] busy_poll_test./251 is trying to acquire lock:
[   10.075902][  T251] ffffffff881f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x50/0x90
[   10.076266][  T251] 
[   10.076266][  T251] but task is already holding lock:
[   10.076539][  T251] ffffffff881f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x50/0x90
[   10.076897][  T251] 
[   10.076897][  T251] other info that might help us debug this:
[   10.077212][  T251]  Possible unsafe locking scenario:
[   10.077212][  T251] 
[   10.077462][  T251]        CPU0
[   10.077588][  T251]        ----
[   10.077712][  T251]   lock((netdev_chain).rwsem);
[   10.077878][  T251]   lock((netdev_chain).rwsem);
[   10.078052][  T251] 
[   10.078052][  T251]  *** DEADLOCK ***
[   10.078052][  T251] 
[   10.078299][  T251]  May be due to missing lock nesting notation
[   10.078299][  T251] 
[   10.078544][  T251] 8 locks held by busy_poll_test./251:
[   10.078714][  T251]  #0: ffff88800b0443f0 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0xf8/0x1d0
[   10.079017][  T251]  #1: ffff88800c148e88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x20b/0x460
[   10.079320][  T251]  #2: ffff888009530910 (kn->active#33){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22e/0x460
[   10.079656][  T251]  #3: ffffffffc060e628 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x12a/0x690 [netdevsim]
[   10.080049][  T251]  #4: ffff888005b720e8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x76/0x3f0
[   10.080354][  T251]  #5: ffff888005b73a50 (&devlink->lock_key){+.+.}-{4:4}, at: nsim_drv_probe+0xb7/0x8b0 [netdevsim]
[   10.080703][  T251]  #6: ffffffff88207e88 (rtnl_mutex){+.+.}-{4:4}, at: nsim_create+0x46a/0xa60 [netdevsim]
[   10.081009][  T251]  #7: ffffffff881f6a70 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x50/0x90
[   10.081360][  T251] 
[   10.081360][  T251] stack backtrace:
[   10.081569][  T251] CPU: 0 UID: 0 PID: 251 Comm: busy_poll_test. Not tainted 6.13.0-rc5-virtme #1
[   10.081858][  T251] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   10.082066][  T251] Call Trace:
[   10.082194][  T251]  <TASK>
[   10.082283][  T251]  dump_stack_lvl+0x82/0xd0
[   10.082454][  T251]  print_deadlock_bug+0x40a/0x650
[   10.082629][  T251]  validate_chain+0x5bf/0xae0
[   10.082801][  T251]  ? __pfx_validate_chain+0x10/0x10
[   10.082972][  T251]  ? hlock_class+0x4e/0x130
[   10.083138][  T251]  ? mark_lock+0x38/0x3e0
[   10.083267][  T251]  __lock_acquire+0xb9a/0x1680
[   10.083436][  T251]  ? udp_tunnel_nic_netdevice_event+0xd1/0x5c0
[   10.083648][  T251]  ? really_probe+0x1df/0x920
[   10.083816][  T251]  lock_acquire.part.0+0xeb/0x330
[   10.083986][  T251]  ? blocking_notifier_call_chain+0x50/0x90
[   10.084195][  T251]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   10.084403][  T251]  ? find_held_lock+0x2c/0x110
[   10.084569][  T251]  ? __pfx_lock_acquire.part.0+0x10/0x10
[   10.084737][  T251]  ? trace_lock_acquire+0x14c/0x1f0
[   10.084905][  T251]  ? lock_acquire+0x32/0xc0
[   10.085074][  T251]  ? blocking_notifier_call_chain+0x50/0x90
[   10.085287][  T251]  down_read+0x9f/0x340
[   10.085419][  T251]  ? blocking_notifier_call_chain+0x50/0x90
[   10.085628][  T251]  ? __pfx_down_read+0x10/0x10
[   10.085796][  T251]  ? notifier_call_chain+0xcd/0x150
[   10.085966][  T251]  blocking_notifier_call_chain+0x50/0x90
[   10.086136][  T251]  call_netdevice_notifiers+0x71/0xa0
[   10.086306][  T251]  ? __pfx_call_netdevice_notifiers+0x10/0x10
[   10.086519][  T251]  ? mutex_is_locked+0x1c/0x60
[   10.086688][  T251]  udp_tunnel_nic_register+0x591/0x870
[   10.086859][  T251]  udp_tunnel_nic_netdevice_event+0x11d/0x5c0
[   10.087070][  T251]  notifier_call_chain+0xcd/0x150
[   10.087239][  T251]  blocking_notifier_call_chain+0x66/0x90
[   10.087408][  T251]  register_netdevice+0xe75/0x1360
[   10.087581][  T251]  ? __pfx_register_netdevice+0x10/0x10
[   10.087751][  T251]  nsim_create+0x6c2/0xa60 [netdevsim]
[   10.087933][  T251]  __nsim_dev_port_add+0x22f/0x6e0 [netdevsim]
[   10.088150][  T251]  ? mark_lock+0x38/0x3e0
[   10.088279][  T251]  ? __pfx___nsim_dev_port_add+0x10/0x10 [netdevsim]
[   10.088500][  T251]  ? lockdep_hardirqs_on_prepare+0x275/0x410
[   10.088709][  T251]  nsim_dev_port_add_all+0x39/0xf0 [netdevsim]
[   10.088931][  T251]  nsim_drv_probe+0x61e/0x8b0 [netdevsim]
[   10.089110][  T251]  ? __pfx_nsim_drv_probe+0x10/0x10 [netdevsim]
[   10.089328][  T251]  ? kernfs_create_link+0x173/0x240
[   10.089495][  T251]  ? kernfs_put+0x1c/0x40
[   10.089624][  T251]  ? sysfs_do_create_link_sd+0x8c/0x100
[   10.089794][  T251]  really_probe+0x1df/0x920
[   10.089965][  T251]  __driver_probe_device+0x2e6/0x3e0
[   10.090133][  T251]  driver_probe_device+0x49/0x140
[   10.090304][  T251]  __device_attach_driver+0x192/0x2b0
[   10.090472][  T251]  ? __pfx___device_attach_driver+0x10/0x10
[   10.090679][  T251]  bus_for_each_drv+0x107/0x1a0
[   10.090847][  T251]  ? __pfx_bus_for_each_drv+0x10/0x10
[   10.091016][  T251]  ? bus_to_subsys+0xd5/0x110
[   10.091186][  T251]  ? __pfx___lock_release+0x10/0x10
[   10.091363][  T251]  ? __pfx_lock_acquire.part.0+0x10/0x10
[   10.091533][  T251]  __device_attach+0x1a3/0x3f0
[   10.091702][  T251]  ? __pfx___device_attach+0x10/0x10
[   10.091869][  T251]  ? bus_to_subsys+0xd5/0x110
[   10.092035][  T251]  ? do_raw_spin_unlock+0x58/0x220
[   10.092204][  T251]  bus_probe_device+0x133/0x180
[   10.092375][  T251]  device_add+0x99d/0x1110
[   10.092544][  T251]  ? __pfx_device_add+0x10/0x10
[   10.092711][  T251]  ? __init_waitqueue_head+0xcf/0x150
[   10.092884][  T251]  new_device_store+0x393/0x690 [netdevsim]
[   10.093105][  T251]  ? __pfx_new_device_store+0x10/0x10 [netdevsim]
[   10.093326][  T251]  ? __pfx_sysfs_kf_write+0x10/0x10
[   10.093493][  T251]  ? sysfs_file_ops+0x11e/0x170
[   10.093667][  T251]  ? __pfx_sysfs_kf_write+0x10/0x10
[   10.093835][  T251]  kernfs_fop_write_iter+0x2ba/0x460
[   10.094003][  T251]  vfs_write+0xa81/0x11e0
[   10.094131][  T251]  ? __pfx_vfs_write+0x10/0x10
[   10.094299][  T251]  ? __lock_release+0x103/0x460
[   10.094467][  T251]  ? do_user_addr_fault+0x972/0xe30
[   10.094638][  T251]  ? __pfx___up_read+0x10/0x10
[   10.094809][  T251]  ksys_write+0xf8/0x1d0
[   10.094941][  T251]  ? __pfx_ksys_write+0x10/0x10
[   10.095110][  T251]  ? do_user_addr_fault+0x97c/0xe30
[   10.095280][  T251]  do_syscall_64+0xc1/0x1d0
[   10.095451][  T251]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   10.095659][  T251] RIP: 0033:0x7f5f6f90fb77
[   10.095832][  T251] Code: 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[   10.096425][  T251] RSP: 002b:00007ffc632b9fa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   10.096676][  T251] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f5f6f90fb77
[   10.096928][  T251] RDX: 0000000000000004 RSI: 000055fb2d1d9f80 RDI: 0000000000000001
[   10.097185][  T251] RBP: 000055fb2d1d9f80 R08: 0000000000000003 R09: 0000000000000000
[   10.097437][  T251] R10: 0000000000000020 R11: 0000000000000246 R12: 0000000000000004
[   10.097689][  T251] R13: 00007f5f6f9cb760 R14: 0000000000000004 R15: 00007f5f6f9c69c0
[   10.097944][  T251]  </TASK>
[   10.183989][  T255] netdevsim netdevsim462 eni462np1: renamed from eth0
[   10.279828][  T254] netdevsim netdevsim546 eni546np1: renamed from eth1