============================================ WARNING: possible recursive locking detected 4.16.0-rc7+ #7 Not tainted -------------------------------------------- syz-executor3/23446 is trying to acquire lock: (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] spin_lock include/linux/spinlock.h:310 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 but task is already holding lock: (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] spin_lock include/linux/spinlock.h:310 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 11 locks held by syz-executor3/23446: #0: (sk_lock-AF_INET){+.+.}, at: [<000000002989cd52>] lock_sock include/net/sock.h:1464 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [<000000002989cd52>] sctp_connect+0x23/0xf0 net/sctp/socket.c:4294 #1: (rcu_read_lock){....}, at: [<0000000031a0784d>] read_pnet include/net/net_namespace.h:280 [inline] #1: (rcu_read_lock){....}, at: [<0000000031a0784d>] sock_net include/net/sock.h:2306 [inline] #1: (rcu_read_lock){....}, at: [<0000000031a0784d>] ip_queue_xmit+0x9e/0x1920 net/ipv4/ip_output.c:429 #2: (rcu_read_lock_bh){....}, at: [<000000002520ae81>] lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #2: (rcu_read_lock_bh){....}, at: [<000000002520ae81>] ip_finish_output2+0x2aa/0x1550 net/ipv4/ip_output.c:213 #3: (rcu_read_lock_bh){....}, at: [<0000000041967349>] __dev_queue_xmit+0x2fe/0x2fc0 net/core/dev.c:3491 #4: (rcu_read_lock){....}, at: [<000000006d7eb171>] br_dev_xmit+0x11d/0x1550 net/bridge/br_device.c:43 #5: (rcu_read_lock_bh){....}, at: [<0000000041967349>] __dev_queue_xmit+0x2fe/0x2fc0 net/core/dev.c:3491 #6: (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] spin_lock include/linux/spinlock.h:310 [inline] #6: (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] #6: (_xmit_ETHER#2){+.-.}, at: [<00000000d58c5eee>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 #7: (rcu_read_lock_bh){....}, at: [<000000002520ae81>] lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #7: (rcu_read_lock_bh){....}, at: [<000000002520ae81>] ip_finish_output2+0x2aa/0x1550 net/ipv4/ip_output.c:213 #8: (rcu_read_lock_bh){....}, at: [<0000000041967349>] __dev_queue_xmit+0x2fe/0x2fc0 net/core/dev.c:3491 #9: (rcu_read_lock){....}, at: [<000000006d7eb171>] br_dev_xmit+0x11d/0x1550 net/bridge/br_device.c:43 #10: (rcu_read_lock_bh){....}, at: [<0000000041967349>] __dev_queue_xmit+0x2fe/0x2fc0 net/core/dev.c:3491 stack backtrace: CPU: 1 PID: 23446 Comm: syz-executor3 Not tainted 4.16.0-rc7+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_deadlock_bug kernel/locking/lockdep.c:1761 [inline] check_deadlock kernel/locking/lockdep.c:1805 [inline] validate_chain kernel/locking/lockdep.c:2401 [inline] __lock_acquire+0xe8f/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:310 [inline] __netif_tx_lock include/linux/netdevice.h:3561 [inline] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 qdisc_restart net/sched/sch_generic.c:393 [inline] __qdisc_run+0x57d/0x18e0 net/sched/sch_generic.c:401 __dev_xmit_skb net/core/dev.c:3217 [inline] __dev_queue_xmit+0xb8b/0x2fc0 net/core/dev.c:3525 dev_queue_xmit+0x17/0x20 net/core/dev.c:3590 br_dev_queue_push_xmit+0x196/0x5a0 net/bridge/br_forward.c:55 NF_HOOK include/linux/netfilter.h:288 [inline] br_forward_finish+0xc8/0x530 net/bridge/br_forward.c:67 NF_HOOK include/linux/netfilter.h:288 [inline] __br_forward+0x533/0xc80 net/bridge/br_forward.c:112 br_flood+0x665/0x770 net/bridge/br_forward.c:225 br_dev_xmit+0xa68/0x1550 net/bridge/br_device.c:87 __netdev_start_xmit include/linux/netdevice.h:4066 [inline] netdev_start_xmit include/linux/netdevice.h:4075 [inline] xmit_one net/core/dev.c:3026 [inline] dev_hard_start_xmit+0x24e/0xac0 net/core/dev.c:3042 __dev_queue_xmit+0x26bf/0x2fc0 net/core/dev.c:3557 dev_queue_xmit+0x17/0x20 net/core/dev.c:3590 neigh_hh_output include/net/neighbour.h:472 [inline] neigh_output include/net/neighbour.h:480 [inline] ip_finish_output2+0xf4d/0x1550 net/ipv4/ip_output.c:229 ip_finish_output+0x864/0xd60 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:277 [inline] ip_mc_output+0x271/0x1350 net/ipv4/ip_output.c:390 dst_output include/net/dst.h:443 [inline] ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 iptunnel_xmit+0x556/0x810 net/ipv4/ip_tunnel_core.c:91 ip_tunnel_xmit+0x177b/0x3550 net/ipv4/ip_tunnel.c:785 __gre_xmit+0x546/0x8b0 net/ipv4/ip_gre.c:449 erspan_xmit+0x779/0x22a0 net/ipv4/ip_gre.c:728 __netdev_start_xmit include/linux/netdevice.h:4066 [inline] netdev_start_xmit include/linux/netdevice.h:4075 [inline] xmit_one net/core/dev.c:3026 [inline] dev_hard_start_xmit+0x24e/0xac0 net/core/dev.c:3042 sch_direct_xmit+0x40d/0x1140 net/sched/sch_generic.c:327 qdisc_restart net/sched/sch_generic.c:393 [inline] __qdisc_run+0x57d/0x18e0 net/sched/sch_generic.c:401 __dev_xmit_skb net/core/dev.c:3217 [inline] __dev_queue_xmit+0xb8b/0x2fc0 net/core/dev.c:3525 dev_queue_xmit+0x17/0x20 net/core/dev.c:3590 br_dev_queue_push_xmit+0x196/0x5a0 net/bridge/br_forward.c:55 NF_HOOK include/linux/netfilter.h:288 [inline] br_forward_finish+0xc8/0x530 net/bridge/br_forward.c:67 NF_HOOK include/linux/netfilter.h:288 [inline] __br_forward+0x533/0xc80 net/bridge/br_forward.c:112 br_flood+0x665/0x770 net/bridge/br_forward.c:225 br_dev_xmit+0xa68/0x1550 net/bridge/br_device.c:87 __netdev_start_xmit include/linux/netdevice.h:4066 [inline] netdev_start_xmit include/linux/netdevice.h:4075 [inline] xmit_one net/core/dev.c:3026 [inline] dev_hard_start_xmit+0x24e/0xac0 net/core/dev.c:3042 __dev_queue_xmit+0x26bf/0x2fc0 net/core/dev.c:3557 dev_queue_xmit+0x17/0x20 net/core/dev.c:3590 neigh_resolve_output+0x5e2/0xa00 net/core/neighbour.c:1350 neigh_output include/net/neighbour.h:482 [inline] ip_finish_output2+0x91a/0x1550 net/ipv4/ip_output.c:229 ip_finish_output+0x864/0xd60 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:277 [inline] ip_mc_output+0x271/0x1350 net/ipv4/ip_output.c:390 dst_output include/net/dst.h:443 [inline] ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 ip_queue_xmit+0x8c0/0x1920 net/ipv4/ip_output.c:504 sctp_v4_xmit+0x108/0x140 net/sctp/protocol.c:992 sctp_packet_transmit+0x225e/0x3750 net/sctp/output.c:638 sctp_outq_flush+0xabb/0x4060 net/sctp/outqueue.c:911 sctp_outq_uncork+0x5a/0x70 net/sctp/outqueue.c:776 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1807 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1210 [inline] sctp_do_sm+0x4e0/0x6ed0 net/sctp/sm_sideeffect.c:1181 sctp_primitive_ASSOCIATE+0x9d/0xd0 net/sctp/primitive.c:88 __sctp_connect+0x829/0xca0 net/sctp/socket.c:1235 sctp_connect+0xb4/0xf0 net/sctp/socket.c:4307 inet_dgram_connect+0x16b/0x1f0 net/ipv4/af_inet.c:542 SYSC_connect+0x213/0x4a0 net/socket.c:1639 SyS_connect+0x24/0x30 net/socket.c:1620 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454e79 RSP: 002b:00007f37bb424c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007f37bb4256d4 RCX: 0000000000454e79 RDX: 0000000000000010 RSI: 00000000200001c0 RDI: 0000000000000013 RBP: 000000000072bf58 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000059 R14: 00000000006f28f8 R15: 0000000000000001