sctp panic in _mtx_lock_sleep when attempting to connect to a remote machine

I've found a way to reliably panic two machines running 8.0-BETA2.  It
seems that there's a problem with SCTP connection requests being made
at the same time as other network traffic.  The panic I see is:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00

Stack trace:

_mtx_lock_sleep
sctp_lower_sosend
sctp_sosend
kern_sendit
sendit
sendto
sycall
Xfast_syscall

I can trigger it by running the SCTP-enabled version of ncat from
http://www.roe.ch/Nmap_SCTP .  I put a few thousand lines of:

cat /dev/random | ./ncat --sctp 192.168.1.80 2345

into a shell script, where 192.168.1.80 is a machine running 7.2 with
SCTP enabled but no server listening - I mostly see "Connection
refused" errors when I run the script.  When I run the script and at
the same time generate some tcp traffic by running csup for example,
the box panics.

-- 
Bruce