[pull] master from ruby:master

test/ruby/test_sleep.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: false
 require 'test/unit'
 require 'etc'
+require 'timeout'
 
 class TestSleep < Test::Unit::TestCase
   def test_sleep_5sec
@@ -13,4 +14,21 @@ def test_sleep_5sec
       assert_operator(slept, :<=, 6.0, "[ruby-core:18015]: longer than expected")
     end
   end
+
+  def test_sleep_forever_not_woken_by_sigchld
+    begin
+      t = Thread.new do
+        sleep 0.5
+        `echo hello`
+      end
+
+      assert_raise Timeout::Error do
+        Timeout.timeout 2 do
+          sleep # Should block forever
+        end
+      end
+    ensure
+      t.join
+    end
+  end
 end

thread_pthread.c

@@ -1109,10 +1109,9 @@ thread_sched_to_waiting_until_wakeup(struct rb_thread_sched *sched, rb_thread_t
     {
         if (!RUBY_VM_INTERRUPTED(th->ec)) {
             bool can_direct_transfer = !th_has_dedicated_nt(th);
-            th->status = THREAD_STOPPED_FOREVER;
+            // NOTE: th->status is set before and after this sleep outside of this function in `sleep_forever`
             thread_sched_wakeup_next_thread(sched, th, can_direct_transfer);
             thread_sched_wait_running_turn(sched, th, can_direct_transfer);
-            th->status = THREAD_RUNNABLE;
         }
         else {
             RUBY_DEBUG_LOG("th:%u interrupted", rb_th_serial(th));