[ 126.825615][ C2]
[ 126.825721][ C2] ======================================================
[ 126.825839][ C2] WARNING: possible circular locking dependency detected
[ 126.825948][ C2] 7.2.0-rc6-virtme #1 Not tainted
[ 126.826037][ C2] ------------------------------------------------------
[ 126.826144][ C2] swapper/2/0 is trying to acquire lock:
[ 126.826232][ C2] ff1100000d5ba358 (&tbl->lock){+.-.}-{3:3}, at: ___neigh_create+0x2be/0x1070
[ 126.826399][ C2]
[ 126.826399][ C2] but task is already holding lock:
[ 126.826527][ C2] ffa0000000228c98 ((&n->timer)){+.-.}-{0:0}, at: call_timer_fn+0x113/0x4c0
[ 126.826689][ C2]
[ 126.826689][ C2] which lock already depends on the new lock.
[ 126.826689][ C2]
[ 126.826859][ C2]
[ 126.826859][ C2] the existing dependency chain (in reverse order) is:
[ 126.827011][ C2]
[ 126.827011][ C2] -> #1 ((&n->timer)){+.-.}-{0:0}:
[ 126.827143][ C2] __lock_acquire+0x518/0xc20
[ 126.827233][ C2] lock_acquire.part.0+0xbc/0x260
[ 126.827320][ C2] __timer_delete_sync+0xea/0x130
[ 126.827408][ C2] neigh_flush_one+0x4bf/0x650
[ 126.827494][ C2] __neigh_ifdown.isra.0+0x1b5/0xea0
[ 126.827601][ C2] neigh_ifdown+0x10/0x20
[ 126.827689][ C2] fib_netdev_event+0x1a9/0x5d0
[ 126.827779][ C2] notifier_call_chain+0xae/0x300
[ 126.827867][ C2] netif_close_many+0x366/0x710
[ 126.827954][ C2] unregister_netdevice_many_notify+0x671/0x19a0
[ 126.828059][ C2] default_device_exit_batch+0x38b/0x600
[ 126.828166][ C2] ops_undo_list+0x2ce/0x8f0
[ 126.828253][ C2] cleanup_net+0x431/0x890
[ 126.828340][ C2] process_one_work+0xdf8/0x1410
[ 126.828428][ C2] worker_thread+0x4f1/0xd60
[ 126.828515][ C2] kthread+0x367/0x460
[ 126.828601][ C2] ret_from_fork+0x474/0x6b0
[ 126.828691][ C2] ret_from_fork_asm+0x11/0x20
[ 126.828779][ C2]
[ 126.828779][ C2] -> #0 (&tbl->lock){+.-.}-{3:3}:
[ 126.828910][ C2] check_prev_add+0xd8/0xe90
[ 126.828997][ C2] validate_chain+0x6b8/0xc20
[ 126.829083][ C2] __lock_acquire+0x518/0xc20
[ 126.829169][ C2] lock_acquire.part.0+0xbc/0x260
[ 126.829256][ C2] _raw_spin_lock_bh+0x38/0x50
[ 126.829346][ C2] ___neigh_create+0x2be/0x1070
[ 126.829432][ C2] ip6_finish_output2+0xb8b/0x1310
[ 126.829521][ C2] ip6_finish_output+0x646/0xda0
[ 126.829608][ C2] ip6_output+0x23f/0x7f0
[ 126.829696][ C2] ndisc_send_skb+0xba3/0x1520
[ 126.829784][ C2] ndisc_send_ns+0xa9/0x120
[ 126.829871][ C2] ndisc_solicit+0x314/0x480
[ 126.829959][ C2] neigh_probe+0xb3/0x100
[ 126.830045][ C2] neigh_timer_handler+0x191/0x1210
[ 126.830129][ C2] call_timer_fn+0x163/0x4c0
[ 126.830216][ C2] __run_timers+0x68f/0xaa0
[ 126.830303][ C2] run_timer_softirq+0xf0/0x160
[ 126.830388][ C2] handle_softirqs+0x1d8/0x8f0
[ 126.830476][ C2] __irq_exit_rcu+0x103/0x1c0
[ 126.830562][ C2] irq_exit_rcu+0xe/0x30
[ 126.830653][ C2] sysvec_apic_timer_interrupt+0x9d/0xe0
[ 126.830766][ C2] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 126.830875][ C2] pv_native_safe_halt+0xf/0x10
[ 126.830964][ C2] default_idle+0x9/0x10
[ 126.831051][ C2] default_idle_call+0x6e/0xb0
[ 126.831137][ C2] cpuidle_idle_call.constprop.0+0x237/0x410
[ 126.831246][ C2] do_idle+0xd8/0x180
[ 126.831331][ C2] cpu_startup_entry+0x53/0x70
[ 126.831418][ C2] start_secondary+0x204/0x2b0
[ 126.831506][ C2] common_startup_64+0x13e/0x148
[ 126.831594][ C2]
[ 126.831594][ C2] other info that might help us debug this:
[ 126.831594][ C2]
[ 126.831765][ C2] Possible unsafe locking scenario:
[ 126.831765][ C2]
[ 126.831893][ C2] CPU0 CPU1
[ 126.831980][ C2] ---- ----
[ 126.832067][ C2] lock((&n->timer));
[ 126.832135][ C2] lock(&tbl->lock);
[ 126.832244][ C2] lock((&n->timer));
[ 126.832354][ C2] lock(&tbl->lock);
[ 126.832420][ C2]
[ 126.832420][ C2] *** DEADLOCK ***
[ 126.832420][ C2]
[ 126.832546][ C2] 3 locks held by swapper/2/0:
[ 126.832637][ C2] #0: ffa0000000228c98 ((&n->timer)){+.-.}-{0:0}, at: call_timer_fn+0x113/0x4c0
[ 126.832790][ C2] #1: ffffffff8eba1cc0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x175/0x1520
[ 126.832941][ C2] #2: ffffffff8eba1cc0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x11d/0x7f0
[ 126.833092][ C2]
[ 126.833092][ C2] stack backtrace:
[ 126.833200][ C2] CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 7.2.0-rc6-virtme #1 PREEMPT(full)
[ 126.833203][ C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 126.833205][ C2] Call Trace:
[ 126.833207][ C2]
[ 126.833208][ C2] dump_stack_lvl+0x6f/0xa0
[ 126.833211][ C2] print_circular_bug.cold+0x38/0x46
[ 126.833215][ C2] check_noncircular+0x171/0x1a0
[ 126.833217][ C2] ? mark_usage+0x61/0x170
[ 126.833219][ C2] check_prev_add+0xd8/0xe90
[ 126.833221][ C2] validate_chain+0x6b8/0xc20
[ 126.833223][ C2] __lock_acquire+0x518/0xc20
[ 126.833226][ C2] lock_acquire.part.0+0xbc/0x260
[ 126.833227][ C2] ? ___neigh_create+0x2be/0x1070
[ 126.833229][ C2] ? rcu_is_watching+0x15/0xd0
[ 126.833231][ C2] ? lock_acquire+0x13c/0x160
[ 126.833233][ C2] _raw_spin_lock_bh+0x38/0x50
[ 126.833235][ C2] ? ___neigh_create+0x2be/0x1070
[ 126.833236][ C2] ___neigh_create+0x2be/0x1070
[ 126.833238][ C2] ip6_finish_output2+0xb8b/0x1310
[ 126.833240][ C2] ? ip6_xmit+0x1cb0/0x1cb0
[ 126.833241][ C2] ? lock_acquire.part.0+0xbc/0x260
[ 126.833242][ C2] ? find_held_lock+0x2b/0x80
[ 126.833245][ C2] ? __lock_release.isra.0+0x6b/0x1a0
[ 126.833247][ C2] ? ip6_mtu+0x15d/0x310
[ 126.833250][ C2] ip6_finish_output+0x646/0xda0
[ 126.833252][ C2] ip6_output+0x23f/0x7f0
[ 126.833253][ C2] ? ip6_finish_output+0xda0/0xda0
[ 126.833254][ C2] ? lock_acquire.part.0+0xbc/0x260
[ 126.833256][ C2] ? find_held_lock+0x2b/0x80
[ 126.833257][ C2] ? __lock_release.isra.0+0x6b/0x1a0
[ 126.833259][ C2] ? __local_bh_enable_ip+0xa5/0x140
[ 126.833261][ C2] ndisc_send_skb+0xba3/0x1520
[ 126.833263][ C2] ? ndisc_recv_na+0x1090/0x1090
[ 126.833266][ C2] ? __local_bh_enable_ip+0xa5/0x140
[ 126.833268][ C2] ndisc_send_ns+0xa9/0x120
[ 126.833270][ C2] ? ndisc_router_discovery+0x2a90/0x2a90
[ 126.833272][ C2] ? lockdep_hardirqs_on_prepare.part.0+0x9a/0x160
[ 126.833274][ C2] ? lockdep_hardirqs_on+0x8c/0x130
[ 126.833275][ C2] ? _raw_spin_unlock_irqrestore+0x53/0x80
[ 126.833277][ C2] ndisc_solicit+0x314/0x480
[ 126.833279][ C2] ? ndisc_send_ns+0x120/0x120
[ 126.833280][ C2] ? __lock_release.isra.0+0x6b/0x1a0
[ 126.833282][ C2] ? neigh_probe+0x62/0x100
[ 126.833284][ C2] ? neigh_periodic_work+0xa60/0xa60
[ 126.833285][ C2] neigh_probe+0xb3/0x100
[ 126.833287][ C2] neigh_timer_handler+0x191/0x1210
[ 126.833289][ C2] ? neigh_periodic_work+0xa60/0xa60
[ 126.833290][ C2] ? rcu_is_watching+0x15/0xd0
[ 126.833291][ C2] call_timer_fn+0x163/0x4c0
[ 126.833293][ C2] ? detach_if_pending+0x1d0/0x1d0
[ 126.833295][ C2] ? find_held_lock+0x2b/0x80
[ 126.833296][ C2] ? __lock_release.isra.0+0x6b/0x1a0
[ 126.833298][ C2] ? rcu_is_watching+0x15/0xd0
[ 126.833300][ C2] __run_timers+0x68f/0xaa0
[ 126.833301][ C2] ? neigh_periodic_work+0xa60/0xa60
[ 126.833303][ C2] ? __bpf_trace_itimer_expire+0x10/0x10
[ 126.833305][ C2] ? __lock_acquire+0x518/0xc20
[ 126.833308][ C2] ? __rwlock_init+0x150/0x150
[ 126.833311][ C2] run_timer_softirq+0xf0/0x160
[ 126.833312][ C2] ? clockevents_program_event+0x307/0x7e0
[ 126.833315][ C2] ? __run_timers+0xaa0/0xaa0
[ 126.833317][ C2] ? trace_irq_enable.constprop.0+0x9b/0x160
[ 126.833319][ C2] ? rcu_is_watching+0x15/0xd0
[ 126.833321][ C2] handle_softirqs+0x1d8/0x8f0
[ 126.833323][ C2] ? _local_bh_enable+0xd0/0xd0
[ 126.833325][ C2] __irq_exit_rcu+0x103/0x1c0
[ 126.833326][ C2] irq_exit_rcu+0xe/0x30
[ 126.833328][ C2] sysvec_apic_timer_interrupt+0x9d/0xe0
[ 126.833330][ C2]
[ 126.833330][ C2]
[ 126.833331][ C2] ? lockdep_hardirqs_on+0x8c/0x130
[ 126.833332][ C2] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 126.833334][ C2] RIP: 0010:pv_native_safe_halt+0xf/0x10
[ 126.833336][ C2] Code: 48 8b 3d 44 21 f6 01 e8 1f 00 00 00 48 2b 05 08 42 91 00 c3 0f 1f 80 00 00 00 00 f3 0f 1e fa eb 07 0f 00 2d a3 4d 0d 00 fb f4 0f 1f 40 d6 48 83 ec 20 8b 17 49 89 f8 83 e2 fe 41 89 d2 0f 01
[ 126.833338][ C2] RSP: 0018:ffa0000000157e00 EFLAGS: 00000282
[ 126.833340][ C2] RAX: 0000000000b343d1 RBX: ff11000001bc46c0 RCX: ffffffff8b8e6de7
[ 126.833341][ C2] RDX: ff11000001bc46c0 RSI: ffffffff8e6358e3 RDI: ffffffff8e07a8e0
[ 126.833342][ C2] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 126.833343][ C2] R10: 0000000000000002 R11: 0000000000000001 R12: 1ff400000002afc3
[ 126.833343][ C2] R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
[ 126.833345][ C2] ? cpuidle_idle_call.constprop.0+0x237/0x410
[ 126.833347][ C2] default_idle+0x9/0x10
[ 126.833349][ C2] default_idle_call+0x6e/0xb0
[ 126.833351][ C2] cpuidle_idle_call.constprop.0+0x237/0x410
[ 126.833352][ C2] ? arch_cpu_idle_exit+0x40/0x40
[ 126.833354][ C2] ? mark_tsc_async_resets+0x30/0x30
[ 126.833355][ C2] ? trace_irq_enable.constprop.0+0x9b/0x160
[ 126.833357][ C2] ? rcu_is_watching+0x15/0xd0
[ 126.833358][ C2] do_idle+0xd8/0x180
[ 126.833360][ C2] cpu_startup_entry+0x53/0x70
[ 126.833361][ C2] start_secondary+0x204/0x2b0
[ 126.833363][ C2] ? set_cpu_sibling_map+0x2130/0x2130
[ 126.833365][ C2] common_startup_64+0x13e/0x148
[ 126.833368][ C2]