[PATCH] simplify do_signal_stop() && utrace_report_jctl() interaction

[Roland McGrath]

> Roland, I think it better to change tracehook definition more, please
> see below.

I don't really object to this in principle.  But this touches signal.c a
lot more in less obviously-trivial ways than my tracehook patch.  That is
more of an issue at the outset than some extra fiddling in the utrace code.
I think we should consider this for a later clean-up after merging.

> BTW. exit_signals() calls tracehook_notify_jctl(why => CLD_STOPPED),
> could you confirm this is right?

Yes, it's right.  I considered passing CLD_EXITED here to distinguish this
odd case, but that would make the vanilla tracehook_notify_jctl()
definition less simple.  Instead, we put the onus on a ->report_jctl hook
to check for PF_EXITING to tell if it's really going to stop.


Thanks,
Roland