> This is the minimal temporary ugly fix for now, we should certainly > cleanup and simplify this logic. The barriers in mark_engine_detached() > and in start_callback() can't help and should be removed. If we ignore > utrace_get_signal() we do not even need utrace_detached_quiesce(), > start_callback() could just do
Agreed. I applied the patch for now. > I think in the longer term mark_engine_detached() should not change > engine->flags at all but add QUIESCE to ->utrace_flags. However, this > breaks utrace_maybe_reap(reap => true) and we should avoid the race > with finish_callback() which clears ->reporting after report_quiesce(). What's the benefit to adding QUIESCE? If any utrace code gets entered at all, then any callback run will be able to do the special-case ops check for detached engines. > A bit off-topic, but I don't think finish_callback() should check > engine->ops == &utrace_detached_ops before return. Instead we should > change finish_callback_report() to return the boolean. We shouldn't > return true without setting report->detaches. Ok. Thanks, Roland
