Introduce xxx_utrace_stop() which notifies engine we are going to stop.
It calls report_quiesce(0), but report.action = UTRACE_STOP instead of
UTRACE_RESUME.
I don't think this is necessary to go along with the ptrace cooperation
hacks. For any engine, there could always be a later engine
Introduce xxx_utrace_stop() which notifies engine we are going to stop.
It calls report_quiesce(0), but report.action = UTRACE_STOP instead of
UTRACE_RESUME.
Change ptrace_stop() to use xxx_utrace_stop(). Yes, it is racy and can
stop after detach, but afaics this is fixeable when utrace_stop()
