panic in arp_rtrequest() FreeBSD 5.3-STABLE from Thu Oct 21

I'm experiencing crashes every time I run zebra in 5.3 around BETA7 (at 
least after BETA3)
I happens less than 20 sec after I run zebra (that means on route update 
from other router).

Here is the back trace (I was not able to save the panic message because 
the machine just hangs and thus do not produce core dump - dumpdev is 
set ...) :

Program received signal SIGSEGV, Segmentation fault.
0xc0500d05 in arp_rtrequest (req=0, rt=0xc18a5318, info=0xd8d7ab58)
    at ../../../netinet/if_ether.c:180
180                     if ((rt->rt_flags & RTF_HOST) == 0 &&
(kgdb) l 180
175                     /*
176                      * XXX: If this is a manually added route to 
interface
177                      * such as older version of routed or gated 
might provid
e,
178                      * restore cloning bit.
179                      */
180                     if ((rt->rt_flags & RTF_HOST) == 0 &&
181                         SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
182                             rt->rt_flags |= RTF_CLONING;
183                     if (rt->rt_flags & RTF_CLONING) {
184                             /*
(kgdb) p rt->rt_flags
$2 = 32769

#0  0xc0500d05 in arp_rtrequest (req=0, rt=0xc18a5318, info=0xd8d7ab58)
    at ../../../netinet/if_ether.c:180
#1  0xc04fe6eb in rtrequest1 (req=1, info=0xd8d7ab58, ret_nrt=0xd8d7ab44)
    at ../../../net/route.c:862
#2  0xc04ff7f3 in route_output (m=0xc171f300, so=0xc1b40144)
    at ../../../net/rtsock.c:396
#3  0xc04fd40c in raw_usend (so=0x0, flags=0, m=0x8001, nam=0x0, 
control=0x0,
    td=0xc1b33000) at ../../../net/raw_usrreq.c:262
#4  0xc04ff5c3 in rts_send (so=0xc1b40144, flags=0, m=0xc171f300, nam=0x0,
    control=0x0, td=0xc1b33000) at ../../../net/rtsock.c:285
#5  0xc04c79e7 in sosend (so=0xc1b40144, addr=0x0, uio=0xd8d7ac88,
    top=0xc171f300, control=0x0, flags=0, td=0xc1b33000)
    at ../../../kern/uipc_socket.c:813
#6  0xc04b79de in soo_write (fp=0x0, uio=0xd8d7ac88, active_cred=0xc1b1f100,
    flags=0, td=0xc1b33000) at ../../../kern/sys_socket.c:115
#7  0xc04b1884 in dofilewrite (td=0xc1b33000, fp=0xc177183c, fd=5, buf=0x0,
    nbyte=128, offset=Unhandled dwarf expression opcode 0x93
) at file.h:246
#8  0xc04b1731 in write (td=0xc1b33000, uap=0xd8d7ad14)
    at ../../../kern/sys_generic.c:282
#9  0xc0593e8b in syscall (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 16, tf_esi = 
134703916, tf_e
bp = -1077942232, tf_isp = -656953996, tf_ebx = -1077942752, tf_edx = 
-107794288
0, tf_ecx = 0, tf_eax = 4, tf_trapno = 0, tf_err = 2, tf_eip = 
672699703, tf_cs
= 31, tf_eflags = 514, tf_esp = -1077942900, tf_ss = 47})
    at ../../../i386/i386/trap.c:1001
#10 0xc0587caf in Xint0x80_syscall () at ../../../i386/i386/exception.s:201

I'll try to find out that is happening but may be someone could figure 
it out faster...