adrian asked met to report the following lor's which according to him are multicast related. FreeBSD 11.0-CURRENT #2 r272097M: Thu Sep 25 11:39:07 CEST 2014 root@crashalot.rainbow-runner.nl:/usr/obj/usr/src/sys/GENERIC amd64 FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512 lock order reversal: 1st 0xfffff8000ac0b990 if_addr_lock (if_addr_lock) @ /usr/src/sys/netinet/igmp.c:1716 2nd 0xffffffff81a64ec0 ifnet_rw (ifnet_rw) @ /usr/src/sys/net/if.c:246 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe01e99da4b0 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe01e99da560 witness_checkorder() at witness_checkorder+0xdc2/frame 0xfffffe01e99da5f0 __rw_rlock() at __rw_rlock+0x9a/frame 0xfffffe01e99da690 ifnet_byindex() at ifnet_byindex+0x22/frame 0xfffffe01e99da6b0 igmp_intr() at igmp_intr+0x1f/frame 0xfffffe01e99da730 netisr_dispatch_src() at netisr_dispatch_src+0x86/frame 0xfffffe01e99da7a0 igmp_v1v2_queue_report() at igmp_v1v2_queue_report+0x186/frame 0xfffffe01e99da7e0 igmp_fasttimo() at igmp_fasttimo+0x3ee/frame 0xfffffe01e99da8c0 pffasttimo() at pffasttimo+0x54/frame 0xfffffe01e99da8f0 softclock_call_cc() at softclock_call_cc+0x19c/frame 0xfffffe01e99da9d0 softclock() at softclock+0x47/frame 0xfffffe01e99da9f0 intr_event_execute_handlers() at intr_event_execute_handlers+0x93/frame 0xfffffe01e99daa30 ithread_loop() at ithread_loop+0xa6/frame 0xfffffe01e99daa70 fork_exit() at fork_exit+0x84/frame 0xfffffe01e99daab0 fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe01e99daab0 --- trap 0, rip = 0, rsp = 0xfffffe01e99dab70, rbp = 0 --- lock order reversal: 1st 0xfffff8000ac0b990 if_addr_lock (if_addr_lock) @ /usr/src/sys/netinet/igmp.c:1716 2nd 0xfffffe00016e2048 ath0_tx_lock (ath0_tx_lock) @ /usr/src/sys/net80211/ieee80211_output.c:228 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe01e99da320 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe01e99da3d0 witness_checkorder() at witness_checkorder+0xdc2/frame 0xfffffe01e99da460 __mtx_lock_flags() at __mtx_lock_flags+0xa8/frame 0xfffffe01e99da4b0 ieee80211_vap_pkt_send_dest() at ieee80211_vap_pkt_send_dest+0x1f0/frame 0xfffffe01e99da500 ieee80211_vap_transmit() at ieee80211_vap_transmit+0x317/frame 0xfffffe01e99da550 ether_output() at ether_output+0x5b1/frame 0xfffffe01e99da5c0 ip_output() at ip_output+0x114d/frame 0xfffffe01e99da6b0 igmp_intr() at igmp_intr+0x2fb/frame 0xfffffe01e99da730 netisr_dispatch_src() at netisr_dispatch_src+0x86/frame 0xfffffe01e99da7a0 igmp_v1v2_queue_report() at igmp_v1v2_queue_report+0x186/frame 0xfffffe01e99da7e0 igmp_fasttimo() at igmp_fasttimo+0x3ee/frame 0xfffffe01e99da8c0 pffasttimo() at pffasttimo+0x54/frame 0xfffffe01e99da8f0 softclock_call_cc() at softclock_call_cc+0x19c/frame 0xfffffe01e99da9d0 softclock() at softclock+0x47/frame 0xfffffe01e99da9f0 intr_event_execute_handlers() at intr_event_execute_handlers+0x93/frame 0xfffffe01e99daa30 ithread_loop() at ithread_loop+0xa6/frame 0xfffffe01e99daa70 fork_exit() at fork_exit+0x84/frame 0xfffffe01e99daab0 fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe01e99daab0 --- trap 0, rip = 0, rsp = 0xfffffe01e99dab70, rbp = 0 ---