thread.c: fix deadlock

* thread.c (thread_join_sleep): the target thread may exit during
  `RUBY_VM_CHECK_INTS_BLOCKING`, but `sleep_forever` does not
  consider the condition change to wait.
  [ruby-core:84248] [Bug #14181]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61274 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_thread.rb

@@ -1249,4 +1249,42 @@ q.pop
       end
     _end
   end
+
+  def test_signal_at_join
+    if /mswin|mingw/ =~ RUBY_PLATFORM
+      skip "can't trap a signal from another process on Windows"
+      # opt = {new_pgroup: true}
+    end
+    assert_separately([], "#{<<~"{#"}\n#{<<~'};'}")
+    {#
+      n = 1000
+      sig = :INT
+      trap(sig) {}
+      IO.popen([EnvUtil.rubybin, "-e", "#{<<~"{#1"}\n#{<<~'};#1'}"], "r+") do |f|
+        tpid = #{$$}
+        sig = :#{sig}
+        {#1
+          STDOUT.sync = true
+          while gets
+            puts
+            Process.kill(sig, tpid)
+          end
+        };#1
+        assert_nothing_raised do
+          n.times do
+            w = Thread.start do
+              sleep 30
+            end
+            begin
+              f.puts
+              f.gets
+            ensure
+              w.kill
+              w.join
+            end
+          end
+        end
+      end
+    };
+  end
 end

thread.c

@@ -883,7 +883,13 @@ thread_join_sleep(VALUE arg)
 
     while (target_th->status != THREAD_KILLED) {
 	if (forever) {
-	    sleep_forever(th, TRUE, FALSE);
+	    th->status = THREAD_STOPPED_FOREVER;
+	    th->vm->sleeper++;
+	    rb_check_deadlock(th->vm);
+	    native_sleep(th, 0);
+	    th->vm->sleeper--;
+	    RUBY_VM_CHECK_INTS_BLOCKING(th->ec);
+	    th->status = THREAD_RUNNABLE;
 	}
 	else {
 	    double now = timeofday();