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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 :)