DragonFlyBSD

I found that following program causes kernel panic.

% uname -mrsv
  DragonFly 2.4.1-RELEASE DragonFly v2.4.1-RELEASE #14: Wed Sep 30 18:12:31 PDT
2009     root@test28.backplane.com:/usr/obj/usr/src-misc/sys/GENERIC  i386
  % cat t.c
  #include <stdlib.h>
  #include <stdio.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netinet/in.h>

int main(int argc, char *argv[])
{
    int s;
    int ret;
    int tmp;

s = socket(AF_INET, SOCK_STREAM, 0);
    if (s == -1) { perror("socket"); exit(1); }

ret = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &tmp, 0);
    if (ret == -1) { perror("setsockopt"); exit(1); }

return 0;
  }
  % gcc t.c
  % ./a.out

debugger is started on the console.
The message is follows.
(Since I cannot use copy&paste here, this message may be not a exact copy.)

panic: assertion: !sopt->sopt_val || kva_p(sopt->sopt_val) in soopt_to_kbuf
  Trace beginning at frame 0xd450abe4
  panic(d450ac08,4,c23d6c20,d1c873b0,d450ac14) at panic+0x8c
  panic(0c576283,c05cef2c,c05558f0,d450aca4,d450ac2c) at panic+0x8c
  sopt_to_kbuf(d450aca4,d450ac68,4,4,d450ac78) at soopt_to_kbuf+0x47
  sooptcopyin(d450aca4,d450ac68,4,4,d440ac78) at sooptcopyin+0x14
  sosetopt(c23d6c20,d450aca4,cdfed7a0,d450acf0,0) at sosetopt+0x146
  kern_estsockopt(3,d450aca4,1,ffff,4) at kern_setsockopt+0x4e
  sys_setsockopt(d450acf0,6,1e87,0,d05abb98) at sys_setsockopt+0x75
  syscall2(d450ad40) at syscall2+0x1ef
  Xint0x80_syscall() at Xint0x80_syscall+0x36
  Debugger("panic")
  Stopped at      Debugger+0x34:  movb    $0,in_Debugger,4260
  db>