OS: CentOS 6.5.

After I set multicast_router of bridge and it’s port to 2, like following:
echo 2 > /sys/devices/virtual/net/eth81/bridge/multicast_router
echo 2 > /sys/devices/virtual/net/bond2/brport/multicast_router Then soft lockup occured:
Message from syslogd@node-0 at Jan 9 15:47:12 …
kernel:BUG: soft lockup – CPU#0 stuck for 61s! [swapper:0]
And the call trace is
RIP: 0010:[] [] br_multicast_flood+0x88/0x140 [bridge]
RSP: 0018:ffff88013bc038f0 EFLAGS: 00000246
RAX: ffff88404f816020 RBX: ffff88013bc03940 RCX: ffff88204e40a640
RDX: ffff882002b9ce01 RSI: ffff882002b9ce80 RDI: 0000000000000000
RBP: ffffffff8100bb93 R08: 0000000000000001 R09: 00000000ff09f4a1
R10: ffff88202c884070 R11: 0000000000000000 R12: ffff88013bc03870
R13: ffff882002b9ce80 R14: ffff88013bc03860 R15: ffffffff8151b225
FS: 0000000000000000(0000) GS:ffff88013bc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 00007fa11a942000 CR3: 0000000001a85000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffffffff81a00000, task ffffffff81a8d020)
Stack:
880be7e100028813 ffff882002b9ce80 ffff882002b9ce80 ffffffffa04f3930
00000000880be7e1 ffff882002b9ce80 ffff882002b9ce80 ffff88200286c042
ffff88202ae7c6e0 ffff882002b9ceb8 ffff88013bc03950 ffffffffa04f36d5
Call Trace:

[] ? __br_forward+0x0/0xd0 [bridge]
[] ? br_multicast_forward+0x15/0x20 [bridge]
[] ? br_handle_frame_finish+0x144/0x2a0 [bridge]
[] ? br_nf_pre_routing_finish+0x238/0x350 [bridge]
[] ? br_nf_pre_routing+0x48b/0x7b0 [bridge]
[] ? __kfree_skb+0x47/0xa0
[] ? nf_iterate+0x69/0xb0
[] ? br_handle_frame_finish+0x0/0x2a0 [bridge]
[] ? nf_hook_slow+0x76/0x120
[] ? br_handle_frame_finish+0x0/0x2a0 [bridge]
[] ? br_handle_frame+0x18c/0x250 [bridge]
[] ? __netif_receive_skb+0x529/0x750
[] ? __alloc_skb+0x7a/0x180
[] ? netif_receive_skb+0x58/0x60
[] ? napi_skb_finish+0x50/0x70
[] ? napi_gro_receive+0x39/0x50
[] ? bnx2x_rx_int+0x83f/0x1630 [bnx2x]
[] ? perf_event_task_sched_out+0x4c/0x70
[] ? bnx2x_poll+0x23e/0x2f0 [bnx2x]
[] ? net_rx_action+0x103/0x2f0
[] ? __do_softirq+0xc1/0x1e0
[] ? handle_IRQ_event+0x60/0x170
[] ? call_softirq+0x1c/0x30
[] ? do_softirq+0x65/0xa0
[] ? irq_exit+0x85/0x90
[] ? do_IRQ+0x75/0xf0
[] ? ret_from_intr+0x0/0x11

[] ? mwait_idle+0x77/0xd0
[] ? atomic_notifier_call_chain+0x1a/0x20
[] ? cpu_idle+0xb6/0x110
[] ? rest_init+0x7a/0x80
[] ? start_kernel+0x405/0x411
[] ? x86_64_start_reservations+0x125/0x129
[] ? x86_64_start_kernel+0x115/0x124

Does anyone know the reason?