repeatable panic with truss

Hello,

While running the next commands on the attached program I get a panic 
everytime.

gcc rfk-smtpd.c
truss ./a.out cat
<ctrl-c>
--panic--

Running 5.1-CURRENT from today. I did a 'make world' in a clean /usr/obj 
dir.
System P-II 400Mhz UP, 256 MB, IDE, no acpi enabled.

I hope somebody can repeat this and maybe it helps getting FreeBSD more 
and more stable. (Or maybe it's a known issue.)

Ronald.

PS: I don't have a debugger enabled kernel, so can't give any more output 
for now. But I'm willing to make one if it's needed.
-- 
  Ronald Klop
  Amsterdam, The Netherlands