r35335: Fix bthread_yield nosignal, if the system is idle, the yielded thread…

r35335: Fix bthread_yield nosignal, if the system is idle, the yielded thread may be forever blocked

src/bthread/task_group.cpp

@@ -866,8 +866,8 @@ int TaskGroup::stop_usleep(bthread_t tid) {
 
 void TaskGroup::yield(TaskGroup** pg) {
     TaskGroup* g = *pg;
-    ReadyToRunArgs args = { g->current_tid(), true };
-    g->set_remained(ready_to_run_in_worker_ignoresignal, &args);
+    ReadyToRunArgs args = { g->current_tid(), false };
+    g->set_remained(ready_to_run_in_worker, &args);
     sched(pg);
 }
 

test/bthread_unittest.cpp

@@ -513,3 +513,14 @@ int main(int argc, char** argv) {
     GFLAGS_NS::ParseCommandLineFlags(&argc, &argv, true);
     return RUN_ALL_TESTS();
 }
+
+void* yield_thread(void*) {
+    bthread_yield();
+    return NULL;
+}
+
+TEST_F(test_bthread_suite, yield_single_thread) {
+    bthread_t tid;
+    ASSERT_EQ(0, bthread_start_background(&tid, NULL, yield_thread, NULL));
+    ASSERT_EQ(0, bthread_join(tid, NULL));
+}