parked firefox process: how to analyze?

[Markus W Kilbinger <mk%kilbi.de@localhost>]

Hi!

I'm observing firefox (on my dual cpu i386 machine) run into 'parked'
state:

  load averages:  5.56,  5.34,  4.60                  up 0 days,  0:42   
19:11:36
  127 processes: 4 runnable, 121 sleeping, 2 on CPU
  CPU0 states:  2.5% user, 89.6% nice,  8.0% system,  0.0% interrupt,  0.0% idle
  CPU1 states:  7.5% user, 59.7% nice, 32.8% system,  0.0% interrupt,  0.0% idle
  Memory: 530M Act, 256M Inact, 12M Wired, 50M Exec, 565M File, 1680K Free
  Swap: 1536M Total, 1536M Free
  
    PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
    553 kilbi     79    0  3808K   11M select/0   1:01 29.54% 29.54% xmms
    509 root      79    0  2860K   66M select/1   1:05 15.87% 15.87% XFree86
   1219 kilbi     31    0  2784K   58M parked/1   1:04 14.21% 14.21% firefox-bin

where it becomes more and more unresponsive (sometimes one tab remains
responsive, but mostly the whole firefox becomes stunned), but still
reacts/exits on 'kill [its pid]'.

Is this a (still) known issue / anybody else seeing this with
-current?

How to investigate this state further? (Any gdb / ktrace etc. hint?)

I recompiled -current kernel and userland several times in the
meantime, but this problem remains.

Could some other/older pkgsrc stuff required by firefox, but compiled
against older libpthread's lead to such problems?

Any h{elp,int} appreciated,

Markus.