fix potential race with notify(&block)

We need to assign the notify_thread before assigning the
notification.  Otherwise, there's a chance the notification
could fire and the notify_thread is not properly assigned for
the POSIX_MQ object when the pipe becomes readable.

1 files changed, 1 insertions, 2 deletions

diff --git a/lib/posix_mq.rb b/lib/posix_mq.rb
index 86fa67e..33b54f4 100644
--- a/lib/posix_mq.rb
+++ b/lib/posix_mq.rb
@@ -47,7 +47,7 @@ class POSIX_MQ
     block.arity == 1 or
       raise ArgumentError, "arity of notify block must be 1"
     r, w = IO.pipe
-    thr = Thread.new(r, w, self) do |r, w, mq|
+    self.notify_thread = Thread.new(r, w, self) do |r, w, mq|
       begin
         begin
           r.read(1) or raise Errno::EINTR
@@ -62,7 +62,6 @@ class POSIX_MQ
       end
     end
     self.notify = w
-    self.notify_thread = thr
     nil
   end if RUBY_PLATFORM =~ /linux/