"Random" kernelpanics related to "sbdrops" after the system has been on for a few hours. 

Only process running is Quagga (bgpd,zebra). 
Network traffic is minimum (<= 100kbit/s avg). 
NIC is bge. 
IPV6 is enabled/configured.

Attaching stacktrace. 

VMCORE available at : http://slask.keff.org/vmcore

# kgdb kernel /var/crash/vmcore.1
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This GDB was configured as "i386-marcel-freebsd"...

Unread portion of the kernel message buffer:
panic: sbdrop
cpuid = 0
Uptime: 14h31m24s
Physical memory: 1011 MB
Dumping 154 MB: 139 123 107 91 75 59 43 27 11

Reading symbols from /boot/kernel/acpi.ko...Reading symbols from /boot/kernel/ac                                                                                                      
pi.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/acpi.ko
Reading symbols from /boot/kernel/pf.ko...Reading symbols from /boot/kernel/pf.k                                                                                                      
o.symbols...done.
done.
Loaded symbols for /boot/kernel/pf.ko
#0  doadump () at pcpu.h:196
196     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) backtrace
#0  doadump () at pcpu.h:196
#1  0xc07f8c57 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:418
#2  0xc07f8f29 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:574
#3  0xc08514db in sbdrop_internal (sb=0xc469b5c4, len=293)
    at /usr/src/sys/kern/uipc_sockbuf.c:843
#4  0xc08516ce in sbdrop_locked (sb=0xc469b5c4, len=398)
    at /usr/src/sys/kern/uipc_sockbuf.c:893
#5  0xc0853f90 in soisdisconnected (so=0xc469b4e0)
    at /usr/src/sys/kern/uipc_socket.c:3097
#6  0xc094e32e in tcp_close (tp=0xc5714740)
    at /usr/src/sys/netinet/tcp_subr.c:819
#7  0xc094e4ac in tcp_drop (tp=0xc5714740, errno=61)
    at /usr/src/sys/netinet/tcp_subr.c:699
#8  0xc0953ca2 in tcp_timer_rexmt (xtp=0xc5714740)
    at /usr/src/sys/netinet/tcp_timer.c:455
#9  0xc080b7aa in softclock (dummy=0x0) at /usr/src/sys/kern/kern_timeout.c:274
#10 0xc07d54ab in ithread_loop (arg=0xc4093240)
    at /usr/src/sys/kern/kern_intr.c:1181
#11 0xc07d1c49 in fork_exit (callout=0xc07d5300 <ithread_loop>,
    arg=0xc4093240, frame=0xc3fb1d38) at /usr/src/sys/kern/kern_fork.c:811
#12 0xc0ae50b0 in fork_trampoline () at /usr/src/sys/i386/i386/exception.s:271
(kgdb)

How-To-Repeat: You wait a few hours (~10h).