- if (tmp == NULL) {
- // not alive (yet): leave this thread on the
- // old_all_threads list.
- prev = &(t->global_link);
- next = t->global_link;
- }
- else {
- // alive: move this thread onto the all_threads list.
- next = t->global_link;
- t->global_link = all_threads;
- all_threads = t;
- *prev = next;
- }
- }
+ if (tmp == NULL) {
+ // not alive (yet): leave this thread on the
+ // old_all_threads list.
+ prev = &(t->global_link);
+ next = t->global_link;
+ }
+ else {
+ // alive
+ next = t->global_link;
+ *prev = next;
+
+ // This is a good place to check for blocked
+ // exceptions. It might be the case that a thread is
+ // blocked on delivering an exception to a thread that
+ // is also blocked - we try to ensure that this
+ // doesn't happen in throwTo(), but it's too hard (or
+ // impossible) to close all the race holes, so we
+ // accept that some might get through and deal with
+ // them here. A GC will always happen at some point,
+ // even if the system is otherwise deadlocked.
+ if (t->blocked_exceptions != END_TSO_QUEUE) {
+ t->global_link = exception_threads;
+ exception_threads = t;
+ } else {
+ // move this thread onto the correct threads list.
+ step *new_step;
+ new_step = Bdescr((P_)t)->step;
+ t->global_link = new_step->threads;
+ new_step->threads = t;
+ }
+ }
+ }
+ }
+ }