There is a FOSS Factory bounty (p267) on this task.

IRC, freenode, #hurd, 2011-02-17

<azeem> task 39011c10 deallocating an invalid port 349, most probably a
<azeem> kernel: Page fault (14), code=6
<azeem> Stopped at  0x28b9c7:   orb     %bh,0(%ecx,%edi,2)
<azeem> db> 
<antrik> tschwinge: I doubt the deallocating warning is related to the
  later fault
<tschwinge> antrik: YOu may be right.
<tschwinge> Perhaps it'd be a good idea to add some sort of timestamp to
  Mach messages.
<tschwinge> Like in Linux' dmesg.
<tschwinge> Or just RDTSC (internal processor counter).