merges r21148 from trunk into ruby_1_9_1.

* thread.c (rb_mutex_trylock): return false if Mutex owned
  by current thread.  [ruby-core:20943]
* thread.c (rb_mutex_lock): check dead lock (recursive lock) here.
* test/ruby/test_thread.rb: add a test.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21160 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 26 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 486e0e3f53..7af2b6d241 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Mon Dec 29 11:58:39 2008  Koichi Sasada  <ko1@atdot.net>
+
+	* thread.c (rb_mutex_trylock): return false if Mutex owned
+	  by current thread.  [ruby-core:20943]
+
+	* thread.c (rb_mutex_lock): check dead lock (recursive lock) here.
+
+	* test/ruby/test_thread.rb: add a test.
+
 Mon Dec 29 07:15:16 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* cont.c: small RDoc fix mentioned from <radek.bulat at gmail.com>
diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index 97e58cd9ea..b460cadea9 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -438,6 +438,18 @@ class TestThread < Test::Unit::TestCase
     assert_equal(false, m3.locked?)
   end
 
+  def test_mutex_trylock
+    m = Mutex.new
+    assert_equal(true, m.try_lock)
+    assert_equal(false, m.try_lock, '[ruby-core:20943]')
+
+    Thread.new{
+      assert_equal(false, m.try_lock)
+    }.join
+
+    m.unlock
+  end
+
   def test_recursive_error
     o = Object.new
     def o.inspect
diff --git a/thread.c b/thread.c
index bdf21c50a7..081c3cd507 100644
--- a/thread.c
+++ b/thread.c
@@ -2796,10 +2796,6 @@ rb_mutex_trylock(VALUE self)
     VALUE locked = Qfalse;
     GetMutexPtr(self, mutex);
 
-    if (mutex->th == GET_THREAD()) {
-	rb_raise(rb_eThreadError, "deadlock; recursive locking");
-    }
-
     native_mutex_lock(&mutex->lock);
     if (mutex->th == 0) {
 	mutex->th = GET_THREAD();
@@ -2871,11 +2867,16 @@ lock_interrupt(void *ptr)
 VALUE
 rb_mutex_lock(VALUE self)
 {
+
     if (rb_mutex_trylock(self) == Qfalse) {
 	mutex_t *mutex;
 	rb_thread_t *th = GET_THREAD();
 	GetMutexPtr(self, mutex);
 
+	if (mutex->th == GET_THREAD()) {
+	    rb_raise(rb_eThreadError, "deadlock; recursive locking");
+	}
+
 	while (mutex->th != th) {
 	    int interrupted;
 	    enum rb_thread_status prev_status = th->status;