From f91879a7b548284c93743168acfd11e3d2aeefac Mon Sep 17 00:00:00 2001
From: "NARUSE, Yui" <naruse@airemix.jp>
Date: Wed, 10 Jul 2019 15:49:10 +0900
Subject: [PATCH] handle_interrupt to defend monitor state [Bug #15992]

If an exception is raised from another thread for example Timeout
and this thread is just after `mon_exit`'s `@mon_owner = nil`,
the exception breaks the state of MonitorMixin. To prevent that situation,
it need to block interruption in mon_enter and mon_exit.
---
 lib/monitor.rb | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/monitor.rb b/lib/monitor.rb
index 90847cf330..044219bcbb 100644
--- a/lib/monitor.rb
+++ b/lib/monitor.rb
@@ -225,11 +225,13 @@ module MonitorMixin
   # +MonitorMixin+.
   #
   def mon_synchronize
-    mon_enter
+    # Prevent interrupt on handling interrupts; for example timeout errors
+    # it may break locking state.
+    Thread.handle_interrupt(Exception => :never){ mon_enter }
     begin
       yield
     ensure
-      mon_exit
+      Thread.handle_interrupt(Exception => :never){ mon_exit }
     end
   end
   alias synchronize mon_synchronize