=============================================
[ INFO: possible recursive locking detected ]
4.4.174+ #17 Not tainted
---------------------------------------------
udevd/18828 is trying to acquire lock:
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] spin_lock include/linux/spinlock.h:302 [inline]
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __netif_tx_lock include/linux/netdevice.h:3306 [inline]
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __dev_queue_xmit+0x1439/0x1bb0 net/core/dev.c:3225

but task is already holding lock:
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] spin_lock include/linux/spinlock.h:302 [inline]
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __netif_tx_lock include/linux/netdevice.h:3306 [inline]
 (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __dev_queue_xmit+0x1439/0x1bb0 net/core/dev.c:3225

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(_xmit_TUNNEL6#2);
  lock(_xmit_TUNNEL6#2);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

10 locks held by udevd/18828:
 #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff814acb45>] prepare_bprm_creds+0x55/0x120 fs/exec.c:1225
 #1:  (((&icsk->icsk_retransmit_timer))){+.-...}, at: [<ffffffff8125822e>] lockdep_copy_map include/linux/lockdep.h:165 [inline]
 #1:  (((&icsk->icsk_retransmit_timer))){+.-...}, at: [<ffffffff8125822e>] call_timer_fn+0xde/0x850 kernel/time/timer.c:1175
 #2:  (slock-AF_INET){+.-...}, at: [<ffffffff824457f1>] spin_lock include/linux/spinlock.h:302 [inline]
 #2:  (slock-AF_INET){+.-...}, at: [<ffffffff824457f1>] tcp_write_timer+0x21/0xd0 net/ipv4/tcp_timer.c:559
 #3:  (rcu_read_lock){......}, at: [<ffffffff823cdd2f>] read_pnet include/net/net_namespace.h:267 [inline]
 #3:  (rcu_read_lock){......}, at: [<ffffffff823cdd2f>] sock_net include/net/sock.h:2270 [inline]
 #3:  (rcu_read_lock){......}, at: [<ffffffff823cdd2f>] ip_queue_xmit+0x3f/0x1ab0 net/ipv4/ip_output.c:386
 #4:  (rcu_read_lock_bh){......}, at: [<ffffffff823c4f7b>] ip_finish_output2+0x20b/0x1280 net/ipv4/ip_output.c:193
 #5:  (rcu_read_lock_bh){......}, at: [<ffffffff82245f57>] __dev_queue_xmit+0x1d7/0x1bb0 net/core/dev.c:3161
 #6:  (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] spin_lock include/linux/spinlock.h:302 [inline]
 #6:  (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __netif_tx_lock include/linux/netdevice.h:3306 [inline]
 #6:  (_xmit_TUNNEL6#2){+.-...}, at: [<ffffffff822471b9>] __dev_queue_xmit+0x1439/0x1bb0 net/core/dev.c:3225
 #7:  (slock-AF_INET){+.-...}, at: [<ffffffff82494ab0>] spin_trylock include/linux/spinlock.h:312 [inline]
 #7:  (slock-AF_INET){+.-...}, at: [<ffffffff82494ab0>] icmp_xmit_lock net/ipv4/icmp.c:220 [inline]
 #7:  (slock-AF_INET){+.-...}, at: [<ffffffff82494ab0>] icmp_send+0x480/0x1410 net/ipv4/icmp.c:655
 #8:  (rcu_read_lock_bh){......}, at: [<ffffffff823c4f7b>] ip_finish_output2+0x20b/0x1280 net/ipv4/ip_output.c:193
 #9:  (rcu_read_lock_bh){......}, at: [<ffffffff82245f57>] __dev_queue_xmit+0x1d7/0x1bb0 net/core/dev.c:3161

stack backtrace:
CPU: 0 PID: 18828 Comm: udevd Not tainted 4.4.174+ #17
 0000000000000000 1c9eb5c034f99dbc ffff8801db606ac0 ffffffff81aad1a1
 ffffffff84057a80 ffff8800ba1f0000 ffffffff83ad60f0 ffff8800ba1f09b8
 ffff8800ba1f09d8 ffff8801db606c48 ffffffff813ad6ff 0000000000000000
Call Trace:
 <IRQ>  [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ>  [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813ad6ff>] print_deadlock_bug kernel/locking/lockdep.c:1752 [inline]
 [<ffffffff813ad6ff>] check_deadlock kernel/locking/lockdep.c:1796 [inline]
 [<ffffffff813ad6ff>] validate_chain kernel/locking/lockdep.c:2128 [inline]
 [<ffffffff813ad6ff>] __lock_acquire.cold+0x118/0x592 kernel/locking/lockdep.c:3213
 [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff82717c98>] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline]
 [<ffffffff82717c98>] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151
 [<ffffffff822471b9>] spin_lock include/linux/spinlock.h:302 [inline]
 [<ffffffff822471b9>] __netif_tx_lock include/linux/netdevice.h:3306 [inline]
 [<ffffffff822471b9>] __dev_queue_xmit+0x1439/0x1bb0 net/core/dev.c:3225
 [<ffffffff82247948>] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263
 [<ffffffff8225c136>] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369
 [<ffffffff823c5412>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff823c5412>] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213
 [<ffffffff823cc6e2>] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288
 [<ffffffff823cf9f1>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff823cf9f1>] ip_mc_output+0x251/0xae0 net/ipv4/ip_output.c:347
 [<ffffffff823cd21c>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff823cd21c>] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119
 [<ffffffff823d300e>] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453
 [<ffffffff823d30f4>] ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1473
 [<ffffffff82493b7e>] icmp_push_reply+0x39e/0x510 net/ipv4/icmp.c:381
 [<ffffffff824950fa>] icmp_send+0xaca/0x1410 net/ipv4/icmp.c:727
 [<ffffffff8239f509>] ipv4_link_failure+0x29/0x1d0 net/ipv4/route.c:1172
 [<ffffffff8269c173>] dst_link_failure include/net/dst.h:481 [inline]
 [<ffffffff8269c173>] vti6_xmit net/ipv6/ip6_vti.c:510 [inline]
 [<ffffffff8269c173>] vti6_tnl_xmit+0xb03/0x1800 net/ipv6/ip6_vti.c:549
 [<ffffffff82245071>] __netdev_start_xmit include/linux/netdevice.h:3750 [inline]
 [<ffffffff82245071>] netdev_start_xmit include/linux/netdevice.h:3759 [inline]
 [<ffffffff82245071>] xmit_one net/core/dev.c:2781 [inline]
 [<ffffffff82245071>] dev_hard_start_xmit+0x7c1/0x11e0 net/core/dev.c:2797
 [<ffffffff822473cb>] __dev_queue_xmit+0x164b/0x1bb0 net/core/dev.c:3229
 [<ffffffff82247948>] dev_queue_xmit+0x18/0x20 net/core/dev.c:3263
 [<ffffffff8225c136>] neigh_direct_output+0x16/0x20 net/core/neighbour.c:1369
 [<ffffffff823c5412>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff823c5412>] ip_finish_output2+0x6a2/0x1280 net/ipv4/ip_output.c:213
 [<ffffffff823cc6e2>] ip_finish_output+0x8b2/0xc60 net/ipv4/ip_output.c:288
 [<ffffffff823d04a7>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff823d04a7>] ip_output+0x227/0x4c0 net/ipv4/ip_output.c:362
 [<ffffffff823cd21c>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff823cd21c>] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119
 [<ffffffff823ce58c>] ip_queue_xmit+0x89c/0x1ab0 net/ipv4/ip_output.c:461
 [<ffffffff82431dd4>] __tcp_transmit_skb+0x1904/0x2cf0 net/ipv4/tcp_output.c:1034
 [<ffffffff8243c54a>] tcp_transmit_skb net/ipv4/tcp_output.c:1047 [inline]
 [<ffffffff8243c54a>] __tcp_retransmit_skb+0x5ea/0x1710 net/ipv4/tcp_output.c:2665
 [<ffffffff8243de33>] tcp_retransmit_skb+0x23/0x2c0 net/ipv4/tcp_output.c:2682
 [<ffffffff8244394e>] tcp_retransmit_timer net/ipv4/tcp_timer.c:461 [inline]
 [<ffffffff8244394e>] tcp_retransmit_timer+0x7ee/0x1f70 net/ipv4/tcp_timer.c:379
 [<ffffffff8244548c>] tcp_write_timer_handler+0x3bc/0x700 net/ipv4/tcp_timer.c:543
 [<ffffffff8244588d>] tcp_write_timer+0xbd/0xd0 net/ipv4/tcp_timer.c:561
 [<ffffffff812582dd>] call_timer_fn+0x18d/0x850 kernel/time/timer.c:1185
 [<ffffffff81258ebf>] __run_timers kernel/time/timer.c:1261 [inline]
 [<ffffffff81258ebf>] run_timer_softirq+0x51f/0xb70 kernel/time/timer.c:1444
 [<ffffffff8271bb16>] __do_softirq+0x226/0xa3f kernel/softirq.c:273
 [<ffffffff810e1a8a>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff810e1a8a>] irq_exit+0x10a/0x150 kernel/softirq.c:391
 [<ffffffff8271b24e>] exiting_irq arch/x86/include/asm/apic.h:652 [inline]
 [<ffffffff8271b24e>] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff8271a59d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768
 <EOI>  [<ffffffff812aef93>] ? should_resched arch/x86/include/asm/preempt.h:92 [inline]
 <EOI>  [<ffffffff812aef93>] ? is_module_text_address+0x33/0x50 kernel/module.c:4109
 [<ffffffff8112f548>] __kernel_text_address+0x68/0xa0 kernel/extable.c:103
 [<ffffffff81013549>] print_context_stack+0x59/0xd0 arch/x86/kernel/dumpstack.c:107
 [<ffffffff81012bb9>] dump_trace+0x179/0x390 arch/x86/kernel/dumpstack_64.c:243
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81483f22>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81483f22>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81483f22>] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81484197>] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601
 [<ffffffff8148475f>] kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:554
 [<ffffffff8147fe9c>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff8147fe9c>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff8147fe9c>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff8147fe9c>] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628
 [<ffffffff814c9f83>] getname_kernel+0x53/0x350 fs/namei.c:215
 [<ffffffff814a8278>] open_exec+0x18/0x70 fs/exec.c:833
 [<ffffffff815a2b69>] load_elf_binary+0x789/0x4b80 fs/binfmt_elf.c:755
 [<ffffffff814aba1f>] search_binary_handler fs/exec.c:1475 [inline]
 [<ffffffff814aba1f>] search_binary_handler+0x14f/0x700 fs/exec.c:1453
 [<ffffffff814adc17>] exec_binprm fs/exec.c:1517 [inline]
 [<ffffffff814adc17>] do_execveat_common.isra.0+0x1007/0x1e90 fs/exec.c:1639
 [<ffffffff814af422>] do_execve fs/exec.c:1683 [inline]
 [<ffffffff814af422>] SYSC_execve fs/exec.c:1764 [inline]
 [<ffffffff814af422>] SyS_execve+0x42/0x50 fs/exec.c:1759
 [<ffffffff82718ef5>] stub_execve+0x5/0x5 arch/x86/entry/entry_64.S:440
audit_printk_skb: 9 callbacks suppressed
audit: type=1400 audit(1570119789.319:918): avc:  denied  { create } for  pid=18853 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119789.349:919): avc:  denied  { create } for  pid=18861 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119789.519:920): avc:  denied  { create } for  pid=18853 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=0
device lo left promiscuous mode
audit: type=1400 audit(1570119789.619:921): avc:  denied  { create } for  pid=18853 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119789.659:922): avc:  denied  { create } for  pid=18853 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=0
audit: type=1400 audit(1570119789.849:923): avc:  denied  { create } for  pid=18882 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119790.349:924): avc:  denied  { create } for  pid=18901 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119790.379:925): avc:  denied  { create } for  pid=18908 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119790.489:926): avc:  denied  { create } for  pid=18902 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119790.769:927): avc:  denied  { create } for  pid=18901 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=0
audit_printk_skb: 42 callbacks suppressed
audit: type=1400 audit(1570119794.489:942): avc:  denied  { create } for  pid=19093 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119794.609:943): avc:  denied  { create } for  pid=19100 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119795.039:944): avc:  denied  { create } for  pid=19117 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119795.099:945): avc:  denied  { create } for  pid=19124 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119795.549:946): avc:  denied  { create } for  pid=19150 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119795.579:947): avc:  denied  { create } for  pid=19156 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119796.069:948): avc:  denied  { create } for  pid=19175 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119796.199:949): avc:  denied  { create } for  pid=19186 comm="syz-executor.5" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119796.579:950): avc:  denied  { create } for  pid=19198 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0
audit: type=1400 audit(1570119796.629:951): avc:  denied  { create } for  pid=19205 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0