On 10/22, Roland McGrath wrote:
>
> > Hmm. If task is not stopped then it is current (except
> > utrace_control(DETACH) can play with the dying task).
>
> Right, asynchronous detach was the problematic case I was concerned with.
but asynchronous detach doesn't do utrace_reset(), unless the tracee
is stopped or exiting (->exit_state != 0).
> But the whole problem we have is that we aren't getting to
> that path when we've done a detach, right?
Confused. We already discussed this before,
> OK, I'll do some testing and resend right now. In UTRACE_DETACH case
> reset can be true but the tracee is running. But I don't think it
> makes sense to check target->exit_state == 0, correct?
I think it's OK if it's running with ->exit_state set (or even with just
PF_EXITING set), i.e. already in kernel mode and never going back to
user mode. (Then it's essentially equivalent to calling user_*_step
while racing with a SIGKILL death, which has to be OK.) Any other kind
of running would not be OK.
Probably we misunderstood each other. In any case I agree, that patch
was not good.
Oleg.
