6.99.12/amd64: triggering a panic as unprivileged user

[Thomas Klausner <wiz%NetBSD.org@localhost>]

git clone git://keithp.com/git/fdpassing
cd fdpassing
make
./lostfd

-> instant panic

I don't see the panic string itself. On the screen I see (manually copied):
curlwp 0xfffffe81164b3720 pid 282 lid 1 lowest kstack 0xfffffe811665b000
panic: trap
cpu0: Begin traceback
printf_nolog() at netbsd:printf_nolog
startlwp() at netbsd:startlwp
alltraps() at netbsd:alltraps+0x9e
unp_externalize() at netbsd:unp_externalize+0x16f
soreceive() at netbsd:soreceive+0xf15
do_sys_recvmsg_so() at netbsd:do_sys_recvmsg_so+0x194
do_sys_recvmsg() at netbsd:do_sys_recvmsg+0x51
sys_recvmsg() at netbsd:sys_recvmsg+0x69
syscall() at netbsd:syscall+0x94
--- syscall (number 27) ---
7f7ff78c8fca:
cpu0: End traceback...
uvm_fault(0xfffffe8116567170, 0x0, 2) -> e
fatal page fault in supervisor mode
trap type 6 code 2 rip ffffffff8034bdcc cs 8 rflags 10286 cr2 84 ilevel 8 r
fffe81166420d0
curlwp 0xfffffe8334423560 pid 369 lid 1 lowest kstack 0xfffffe811663f000

dumping to dev 168,2 (offset+..., size=...):
dump 12279

and then it stops, i.e., doesn't dump.
 Thomas