partially merge revision(s) 5f69a7f60467fa58c2f998daffab43e118bff36c: [Backport #17666]

Co-authored-by: Samuel Williams <@ioquatix>
https://github.com/nagachika/ruby/pull/1/commits/2cee515f024f3295945f312cb6b052f972f9c93d

1 files changed, 1 insertions, 1 deletions

diff --git a/thread.c b/thread.c
index 2ee878939b..ec7a9b760f 100644
--- a/thread.c
+++ b/thread.c
@@ -544,7 +544,7 @@ rb_threadptr_join_list_wakeup(rb_thread_t *thread)
     while (join_list) {
         rb_thread_t *target_thread = join_list->thread;
 
-        if (target_thread->scheduler != Qnil) {
+        if (target_thread->scheduler != Qnil && rb_fiberptr_blocking(join_list->fiber) == 0) {
             rb_scheduler_unblock(target_thread->scheduler, target_thread->self, rb_fiberptr_self(join_list->fiber));
         } else {
             rb_threadptr_interrupt(target_thread);