IRC, #hurd, September 2010

<diegonc> when an application executes an out instruction in user mode, how is
  kernel mode entered? general protection trap?
<youpi> some sort of trap, yes
<youpi> I'd rather think about illegal instruction, but yes
<diegonc> hm.. so to debug what happens inside that instruction I'll have to
  break at the trap handler. Can I instruct kdb to stop only when a given task
  caused the trap?
<youpi> applications usually don't trap, so what I usually do is to uncomment
  the test at the end of user_trap() before the call to kdb_trap()
<diegonc> "if (debug_all_traps_with_kdb && .. " <- that test?
<youpi> yes
<youpi> so comment the test to make kdb_trap() called all the time
<diegonc> oh, I understand now :)