Fixed two races.

The first is that the memory_region destructor would complain there is
still an outstanding allocation. This is because circular_buffer from
rust_chan wasn't refing its task, so the task was being destructed too
soon.

The second was where the program could deadlock while joining a
task. The target task would die in the time between checking whether
the task should block and then actually blocking. The fix is to use
the target task's lock.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/rt/rust_task.cpp b/src/rt/rust_task.cpp
index 6c7ab554002..70afcdd9d58 100644
--- a/src/rt/rust_task.cpp
+++ b/src/rt/rust_task.cpp
@@ -118,12 +118,15 @@ void task_start_wrapper(spawn_args *a)
     a->f(&rval, task, a->a3, a->a4);
 
     LOG(task, task, "task exited with value %d", rval);
+    
 
     LOG(task, task, "task ref_count: %d", task->ref_count);
     A(task->sched, task->ref_count >= 0,
       "Task ref_count should not be negative on exit!");
     task->die();
+    task->lock.lock();
     task->notify_tasks_waiting_to_join();
+    task->lock.unlock();
 
     task->yield(1);
 }