From: "ko1 (Koichi Sasada)" Date: 2014-01-06T15:31:13+09:00 Subject: [ruby-core:59572] [ruby-trunk - Bug #9342] [PATCH] SizedQueue#clear does not notify waiting threads in Ruby 1.9.3 Issue #9342 has been updated by ko1 (Koichi Sasada). Category set to ext Assignee set to ko1 (Koichi Sasada) Target version set to current: 2.2.0 ---------------------------------------- Bug #9342: [PATCH] SizedQueue#clear does not notify waiting threads in Ruby 1.9.3 https://bugs.ruby-lang.org/issues/9342#change-44107 Author: jsc (Justin Collins) Status: Open Priority: Normal Assignee: ko1 (Koichi Sasada) Category: ext Target version: current: 2.2.0 ruby -v: ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-darwin11.4.2] Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN In Ruby 1.9.3, when SizedQueue#clear is called, it empties the queue but does not notify waiting threads that the queue is empty. This typically leads to deadlock when the queue is full. For example: sq = SizedQueue.new(1) sq << 1 # Fill queue t1 = Thread.new do sq << 1 # Attempt to add another item to queue, fail and go to sleep waiting end t2 = Thread.new do Thread.pass sq.clear end t2.join # Empty queue t1.join # Deadlock, t1 continues to sleep -- http://bugs.ruby-lang.org/