From: nagachika00@...
Date: 2014-02-09T16:10:38+00:00
Subject: [ruby-core:60626] [ruby-trunk - Bug #9342] [PATCH] SizedQueue#clear does not notify waiting threads in Ruby 1.9.3

Issue #9342 has been updated by Tomoyuki Chikanaga.

Backport changed from 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED to 1.9.3: REQUIRED, 2.0.0: DONE, 2.1: REQUIRED

1.9.3 and 2.0.0 has different implementation of Queue/SizedQueue from 2.1/trunk.
I partially backported r44595 for test, and commited a patch for ruby_2_0_0 at r44899.

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Bug #9342: [PATCH] SizedQueue#clear does not notify waiting threads in Ruby 1.9.3
https://bugs.ruby-lang.org/issues/9342#change-45065

* Author: Justin Collins
* Status: Closed
* Priority: Normal
* Assignee: 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: REQUIRED, 2.0.0: DONE, 2.1: REQUIRED
----------------------------------------
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


---Files--------------------------------
0001-Wake-waiting-threads-when-SizedQueue-clear-is-called.patch (1.73 KB)
0002-Wake-waiting-threads-when-SizedQueue-clear-is-called-2.0.patch (769 Bytes)


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