From 320d7c54ba01a6a19ebec25dadab7196da95f3e7 Mon Sep 17 00:00:00 2001
From: k0kubun <k0kubun@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Fri, 19 Oct 2018 15:08:55 +0000
Subject: [PATCH] mjit.c: don't let MJIT.pause hang on full active units

test/ruby/test_rubyvm_mjit.rb: add reproductive test

[Bug #15071]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65179 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 mjit.c                        |  2 +-
 test/ruby/test_rubyvm_mjit.rb | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/mjit.c b/mjit.c
index 87b4a3e990..6ae68e30b7 100644
--- a/mjit.c
+++ b/mjit.c
@@ -647,7 +647,7 @@ mjit_pause(int wait_p)
         tv.tv_sec = 0;
         tv.tv_usec = 1000;
 
-        while (unit_queue.length > 0) {
+        while (unit_queue.length > 0 && active_units.length < mjit_opts.max_cache_size) { /* inverse of condition that waits for mjit_worker_wakeup */
             CRITICAL_SECTION_START(3, "in mjit_pause for a worker wakeup");
             rb_native_cond_broadcast(&mjit_worker_wakeup);
             CRITICAL_SECTION_FINISH(3, "in mjit_pause for a worker wakeup");
diff --git a/test/ruby/test_rubyvm_mjit.rb b/test/ruby/test_rubyvm_mjit.rb
index ce4940ba2d..b41ad78510 100644
--- a/test/ruby/test_rubyvm_mjit.rb
+++ b/test/ruby/test_rubyvm_mjit.rb
@@ -33,6 +33,18 @@ class TestRubyVMMJIT < Test::Unit::TestCase
     )
   end
 
+  def test_pause_does_not_hang_on_full_units
+    out, _ = eval_with_jit(<<~'EOS', verbose: 1, min_calls: 1, max_cache: 10, wait: false)
+      i = 0
+      while i < 11
+        eval("def mjit#{i}; end; mjit#{i}")
+        i += 1
+      end
+      print RubyVM::MJIT.pause
+    EOS
+    assert_equal('true', out)
+  end
+
   def test_pause_wait_false
     out, err = eval_with_jit(<<~'EOS', verbose: 1, min_calls: 1, wait: false)
       i = 0