Why do we see "udp_conn_timeout:107: assertion condition met" errors on Red Hat Enterprise Linux 6 after dsa_filter module is loaded?

Issue

• Below call traces observed soon after loading dsa_filter module.

 kernel: udp_conn_timeout:107: assertion condition met
 kernel: Pid: 0, comm: swapper Tainted: P           ---------------    2.6.32-358.18.1.el6.x86_64 #1
 kernel: Call Trace:
 kernel: <IRQ>  [<ffffffffa0364ff9>] ? tb_panic+0x19/0x30 [dsa_filter]
 kernel: [<ffffffffa0331427>] ? udp_conn_timeout+0xf7/0x100 [dsa_filter]
 kernel: [<ffffffffa0304529>] ? _lru_cleanup_udp+0x109/0x220 [dsa_filter]
 kernel: [<ffffffff81510bfb>] ? _spin_unlock_bh+0x1b/0x20
 kernel: [<ffffffffa030578e>] ? conntrack_track_udp_conn+0x5e/0x130 [dsa_filter]
 kernel: [<ffffffffa0331538>] ? conn_init_udp+0x108/0x300 [dsa_filter]
 kernel: [<ffffffffa0302474>] ? conntrack_new_connection+0x1a4/0x9c0 [dsa_filter]
 kernel: [<ffffffff81510bfb>] ? _spin_unlock_bh+0x1b/0x20
 kernel: [<ffffffffa03654d2>] ? tb_spin_unlock+0x12/0x20 [dsa_filter]
 kernel: [<ffffffffa032421b>] ? drules_find_virtual_port+0x31b/0x7b0 [dsa_filter]
 kernel: [<ffffffffa032d628>] ? stateful_udp_new_incoming+0x48/0x2c0 [dsa_filter]
 kernel: [<ffffffffa032da78>] ? stateful_udp_new+0x1d8/0x2b0 [dsa_filter]
 kernel: [<ffffffffa032dbf5>] ? stateful_udp_filter+0xa5/0xc0 [dsa_filter]
 kernel: [<ffffffffa032dc55>] ? stateful_process+0x45/0x50 [dsa_filter]
 kernel: [<ffffffffa0316ab8>] ? core_pkt_filter+0x528/0xd10 [dsa_filter]
 kernel: [<ffffffffa03656b0>] ? tb_memcpy+0x10/0x20 [dsa_filter]
 kernel: [<ffffffffa0315101>] ? core_pkt_fetch_header+0x51/0x140 [dsa_filter]
 kernel: [<ffffffffa0315af1>] ? core_pkt_hook+0x391/0xe30 [dsa_filter]
 kernel: [<ffffffff8145fcdd>] ? fib_rules_lookup+0xad/0xf0
 kernel: [<ffffffffa0362f97>] ? lin_nf_packet_wrapper+0x207/0x380 [dsa_filter]
 kernel: [<ffffffffa0363be0>] ? lin_pkt_get_frame_header+0x0/0x4a0 [dsa_filter]
 kernel: [<ffffffffa0363880>] ? lin_pkt_get_length+0x0/0x20 [dsa_filter]
 kernel: [<ffffffffa0363ae0>] ? lin_pkt_read_start+0x0/0x100 [dsa_filter]
 kernel: [<ffffffffa0363940>] ? lin_pkt_read+0x0/0x1a0 [dsa_filter]
 kernel: [<ffffffffa03638f0>] ? lin_pkt_read_end+0x0/0x50 [dsa_filter]
 kernel: [<ffffffffa03638a0>] ? lin_pkt_get_valid_checksum+0x0/0x50 [dsa_filter]
 kernel: [<ffffffff8147f020>] ? ip_rcv_finish+0x0/0x440
 kernel: [<ffffffffa0363249>] ? lin_nf_packet_wrapper_all+0x139/0x170 [dsa_filter]
 kernel: [<ffffffff8147f020>] ? ip_rcv_finish+0x0/0x440
 kernel: [<ffffffffa0363301>] ? lin_nf_packet_wrapper_inet+0x21/0x30 [dsa_filter]
 kernel: [<ffffffff81474d79>] ? nf_iterate+0x69/0xb0
 kernel: [<ffffffff8147f020>] ? ip_rcv_finish+0x0/0x440
 kernel: [<ffffffff81474f34>] ? nf_hook_slow+0x74/0x110
 kernel: [<ffffffff8147f020>] ? ip_rcv_finish+0x0/0x440
 kernel: [<ffffffff81448ae8>] ? __netif_receive_skb+0x6e8/0x750
 kernel: [<ffffffff8147f6c4>] ? ip_rcv+0x264/0x350
 kernel: [<ffffffff814488ab>] ? __netif_receive_skb+0x4ab/0x750
 kernel: [<ffffffff8144ac88>] ? netif_receive_skb+0x58/0x60
 kernel: [<ffffffff8144ad90>] ? napi_skb_finish+0x50/0x70
 kernel: [<ffffffff8144d339>] ? napi_gro_receive+0x39/0x50
 kernel: [<ffffffffa0183a88>] ? e1000_receive_skb+0x58/0x90 [e1000]
 kernel: [<ffffffffa01885b2>] ? e1000_clean_rx_irq+0x2b2/0x5e0 [e1000]
 kernel: [<ffffffffa0185cd1>] ? e1000_clean+0x1f1/0xa50 [e1000]
 kernel: [<ffffffff81065a05>] ? enqueue_entity+0x125/0x410
 kernel: [<ffffffff81065d54>] ? enqueue_task_fair+0x64/0x100
 kernel: [<ffffffff8106327e>] ? try_to_wake_up+0x24e/0x3e0
 kernel: [<ffffffff8144d453>] ? net_rx_action+0x103/0x2f0
 kernel: [<ffffffff810770b1>] ? __do_softirq+0xc1/0x1e0
 kernel: [<ffffffff8100c1cc>] ? call_softirq+0x1c/0x30
 kernel: [<ffffffff8100de05>] ? do_softirq+0x65/0xa0
 kernel: [<ffffffff81076e95>] ? irq_exit+0x85/0x90
 kernel: [<ffffffff815176e5>] ? do_IRQ+0x75/0xf0
 kernel: [<ffffffff8100b9d3>] ? ret_from_intr+0x0/0x11
 kernel: <EOI>  [<ffffffff8103b92b>] ? native_safe_halt+0xb/0x10
 kernel: [<ffffffff81014a4d>] ? default_idle+0x4d/0xb0
 kernel: [<ffffffff81009fc6>] ? cpu_idle+0xb6/0x110
 kernel: [<ffffffff814f397a>] ? rest_init+0x7a/0x80
 kernel: [<ffffffff81c27f7b>] ? start_kernel+0x424/0x430
 kernel: [<ffffffff81c2733a>] ? x86_64_start_reservations+0x125/0x129
 kernel: [<ffffffff81c27438>] ? x86_64_start_kernel+0xfa/0x109