merge revision(s) 62673: [Backport #14577]

	thread.c: deadlock in backtrace

	* thread.c (unblock_function_set): check interrupts just once
	  during raising exceptions, as they are deferred since r16651.
	  [ruby-core:85939] [Bug #14577]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62917 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 24 insertions, 2 deletions

diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index ee212083a3..8eb92faa08 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -1031,6 +1031,28 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
     end;
   end
 
+  def test_blocking_backtrace
+    assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      class Bug < RuntimeError
+        def backtrace
+          IO.readlines(IO::NULL)
+        end
+      end
+      bug = Bug.new '[ruby-core:85939] [Bug #14577]'
+      n = 10000
+      i = 0
+      n.times do
+        begin
+          raise bug
+        rescue Bug
+          i += 1
+        end
+      end
+      assert_equal(n, i)
+    end;
+  end
+
   def test_wrong_backtrace
     assert_separately([], "#{<<-"begin;"}\n#{<<-"end;"}")
     begin;
diff --git a/thread.c b/thread.c
index 0597d2ed8f..d74c731a82 100644
--- a/thread.c
+++ b/thread.c
@@ -385,7 +385,7 @@ set_unblock_function(rb_thread_t *th, rb_unblock_function_t *func, void *arg,
 	}
 
 	native_mutex_lock(&th->interrupt_lock);
-    } while (RUBY_VM_INTERRUPTED_ANY(th) &&
+    } while (!th->raised_flag && RUBY_VM_INTERRUPTED_ANY(th) &&
 	     (native_mutex_unlock(&th->interrupt_lock), TRUE));
 
     if (old) *old = th->unblock;
diff --git a/version.h b/version.h
index 9f8a6df824..93b1cf8ea6 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.4.4"
 #define RUBY_RELEASE_DATE "2018-03-25"
-#define RUBY_PATCHLEVEL 286
+#define RUBY_PATCHLEVEL 287
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 3