Me too :-(

I halted my machine (NetBSD-current / i386) and it hangs. I called
ddb and got a trace to some vm*collapse. I then entered 'boot(100)'
and got a coredump.
Running 'gdb -k' on the dump gives the following:
(kgdb) bt
#0  0x8 in ?? ()
Cannot access memory at address 0x0.
(kgdb) print *curproc
$1 = {p_forw = 0xf827c088, p_back = 0x0, p_list = {le_next = 0xf882ca00, 
    le_prev = 0xf885e708}, p_cred = 0xf87ee460, p_fd = 0x0, 
  p_stats = 0xfb2b02c0, p_limit = 0xf827fc60, p_vmspace = 0xf8838200, 
  p_sigacts = 0xfb2b0194, p_flag = 8196, p_unused = 0 '\000', 
  p_stat = 2 '\002', p_pad1 = "\000", p_pid = 77, p_hash = {le_next = 0x0, 
    le_prev = 0xf87f3d34}, p_pglist = {le_next = 0x0, le_prev = 0xf87ee5a8}, 
  p_pptr = 0xf87fae00, p_sibling = {le_next = 0xf882ca00, 
    le_prev = 0xf885e748}, p_children = {lh_first = 0x0}, p_oppid = 0, 
  p_dupfd = 0, p_estcpu = 204, p_cpticks = 75, p_pctcpu = 837, p_wchan = 0x0, 
  p_wmesg = 0xf81c2785 "scsi_scsi_cmd", p_swtime = 12, p_slptime = 0, 
  p_realtimer = {it_interval = {tv_sec = 0, tv_usec = 0}, it_value = {
      tv_sec = 0, tv_usec = 0}}, p_rtime = {tv_sec = 11, tv_usec = 344570}, 
  p_uticks = 1, p_sticks = 1132, p_iticks = 0, p_traceflag = 0, 
  p_tracep = 0x0, p_siglist = 0, p_textvp = 0xf8859d80, p_holdcnt = 0, 
  p_emul = 0xf81e6a54, p_spare = {0}, p_sigmask = 16384, 
  p_sigignore = 4294967295, p_sigcatch = 540679, p_priority = 17 '\021', 
  p_usrpri = 101 'e', p_nice = 20 '\024', 
  p_comm = "lpd\000\000er\000\000\000\000\000\000\000\000\000", 
  p_pgrp = 0xf87ee5a0, p_thread = 0x0, p_addr = 0xfb2b0000, p_md = {
    md_regs = 0xfb2b1fb0, md_flags = 0}, p_xstat = 0, p_acflag = 3, 
  p_ru = 0xf88a6100}

Any ideas?
> 
> In "Hang during shutdown", Dave Huang <khym@bga.com> wrote: 
> > I first noticed this around 2 weeks ago, I think, and it happened to me 
> > again last night... I did a shutdown -r now to reboot and my machine 
> > seemed to hang while killing off all the processes (or maybe while 
> > waiting for 'em to die or something). It only seems to happen if the 
> > machine's been up for a while though (maybe over a day or so). I went 
> > into ddb and got a stack trace, which showed functions in the VM system, 
> > such as vm_object_collapse (I think). I was in a hurry to reboot, so I 
> > didn't write down the trace.
> 
> I see the same thing.  It happens when killing lpd on my system(s).
> 
> The bug seems to be arch independent, since I can reproduce it on
> NetBSD/Mac, and NetBSd/Sun3.
> 
> ;-/
> 
> -- 
>    //////////////////////////////////////////////////////////////////////
>   //    Scott Ellis     //   scotte@warped.com   //   sellis@gi.com   //
>  //////////////////////////////////////////////////////////////////////
> // WARNING: This signature warps  time and space in its vicinity    //
> 
> 
> 


-- 
Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (W Germany)