Kernel panic all times when running service netif restart

[Otacílio]

Dears

I'm getting a kernel panic all times on

FreeBSD beaglebone 11.0-ALPHA4 FreeBSD 11.0-ALPHA4 #0 r302064: Wed Jun 
22 00:25:52 BRT 2016 
ota at squitch:/root/workdir/crochet/work/obj/arm.armv6/usr/src/sys/BEAGLEBONE 
arm

when I run 'service netif restart' on a beaglebone black using urtwn 
driver.  Look bellow:

root at beaglebone:/usr/home/ota # service netif restart
dhclient not running? (check /var/run/dhclient.cpsw0.pid).
Jun 22 17:53:18 beaglebone dhclient[782]: My address (192.168.0.11) was 
deleted, dhclient exiting
Jun 22 17:53:18 beaglebone dhclient[730]: connection closed
Jun 22 17:53:18 beaglebone dhclient[730]: exiting.
Stopping wpa_supplicant.
Jun 22 17:53:19 beaglebone wpa_supplicant[350]: ioctl[SIOCS80211, op=20, 
val=0, arg_len=7]: Can't assign requested address
dhclient not running? (check /var/run/dhclient.wlan0.pid).
Stopping Network: lo0 cpsw0 wlan0.
lo0: flags=8048<LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
         groups: lo
         nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
cpsw0: flags=8c02<BROADCAST,OACTIVE,SIMPLEX,MULTICAST> metric 0 mtu 1500
         options=8000b<RXCSUM,TXCSUM,VLAN_MTU,LINKSTATE>
         ether 90:59:af:4c:20:9a
         media: Ethernet autoselect (none)
         status: no carrier
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
wlan0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
         ether 14:cc:20:12:ee:55
         groups: wlan
         ssid "" channel 11 (2462 MHz 11g)
         regdomain FCC country US authmode OPEN privacy OFF txpower 30 
bmiss 7
         scanvalid 60 protmode CTS wme
         media: IEEE 802.11 Wireless Ethernet autoselect (autoselect)
         status: no carrier
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
Fatal kernel mode data abort: 'Translation Fault (L2)' on read
trapframe: 0xde3abba0
FSR=00000007, FAR=00000014, spsr=20000013
r0 =00000000, r1 =00000000, r2 =c06f1fa6, r3 =000003aa
r4 =c31fc000, r5 =c06f1fa6, r6 =c2fe84b8, r7 =c2fe6000
r8 =c2fec000, r9 =00000016, r10=c2fec008, r11=de3abc70
r12=c08b6ca0, ssp=de3abc30, slr=c31941e4, pc =c0484744

[ thread pid 1273 tid 100074 ]
Stopped at      if_detach+0x28: ldr     r4, [r0, #0x014]
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