From 8fd5062025a4be33bf816f1060c3259cf1a9d624 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely.gcc@gmail.com>
Date: Thu, 5 Jul 2012 01:10:10 +0000
Subject: [PATCH] re PR libstdc++/53830 (condition_variable_any - deadlock
 issue)

	PR libstdc++/53830
	* include/std/condition_variable (condition_variable_any::wait):
	Move _Unlock type to class scope.
	(condition_variable_any::wait_until): Reuse it.
	* testsuite/30_threads/condition_variable_any/53830.cc: New.

From-SVN: r189275
---
 libstdc++-v3/ChangeLog                        |  8 +++
 libstdc++-v3/include/std/condition_variable   | 48 +++++++------
 .../condition_variable_any/53830.cc           | 68 +++++++++++++++++++
 3 files changed, 104 insertions(+), 20 deletions(-)
 create mode 100644 libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index ff20cb1a197a..6323133f558c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2012-07-05  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+	PR libstdc++/53830
+	* include/std/condition_variable (condition_variable_any::wait):
+	Move _Unlock type to class scope.
+	(condition_variable_any::wait_until): Reuse it.
+	* testsuite/30_threads/condition_variable_any/53830.cc: New.
+
 2012-06-20  Jörg Sonnenberger <joerg@britannica.bec.de>
 	    Jonathan Wakely  <jwakely.gcc@gmail.com>
 
diff --git a/libstdc++-v3/include/std/condition_variable b/libstdc++-v3/include/std/condition_variable
index ff65dc49ce44..0f75d8e446ca 100644
--- a/libstdc++-v3/include/std/condition_variable
+++ b/libstdc++-v3/include/std/condition_variable
@@ -1,6 +1,6 @@
 // <condition_variable> -*- C++ -*-
 
-// Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -171,6 +171,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     condition_variable			_M_cond;
     mutex				_M_mutex;
 
+    // scoped unlock - unlocks in ctor, re-locks in dtor
+    template<typename _Lock>
+      struct _Unlock
+      {
+	explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
+
+	~_Unlock() noexcept(false)
+	{
+	  if (uncaught_exception())
+	    __try { _M_lock.lock(); } __catch(...) { }
+	  else
+	    _M_lock.lock();
+	}
+
+	_Unlock(const _Unlock&) = delete;
+	_Unlock& operator=(const _Unlock&) = delete;
+
+	_Lock& _M_lock;
+      };
+
   public:
     typedef condition_variable::native_handle_type	native_handle_type;
 
@@ -198,21 +218,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       void
       wait(_Lock& __lock)
       {
-	// scoped unlock - unlocks in ctor, re-locks in dtor
-	struct _Unlock {
-	  explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
-	  ~_Unlock() noexcept(false)
-	  {
-	    if (uncaught_exception())
-	      __try { _M_lock.lock(); } __catch(...) { }
-	    else
-	      _M_lock.lock();
-	  }
-	  _Lock& _M_lock;
-	};
-
 	unique_lock<mutex> __my_lock(_M_mutex);
-	_Unlock __unlock(__lock);
+	_Unlock<_Lock> __unlock(__lock);
 	// _M_mutex must be unlocked before re-locking __lock so move
 	// ownership of _M_mutex lock to an object with shorter lifetime.
 	unique_lock<mutex> __my_lock2(std::move(__my_lock));
@@ -233,11 +240,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       wait_until(_Lock& __lock,
 		 const chrono::time_point<_Clock, _Duration>& __atime)
       {
-        unique_lock<mutex> __my_lock(_M_mutex);
-        __lock.unlock();
-        cv_status __status = _M_cond.wait_until(__my_lock, __atime);
-        __lock.lock();
-        return __status;
+	unique_lock<mutex> __my_lock(_M_mutex);
+	_Unlock<_Lock> __unlock(__lock);
+	// _M_mutex must be unlocked before re-locking __lock so move
+	// ownership of _M_mutex lock to an object with shorter lifetime.
+	unique_lock<mutex> __my_lock2(std::move(__my_lock));
+	return _M_cond.wait_until(__my_lock2, __atime);
       }
 
     template<typename _Lock, typename _Clock,
diff --git a/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc b/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc
new file mode 100644
index 000000000000..91aa348f90c8
--- /dev/null
+++ b/libstdc++-v3/testsuite/30_threads/condition_variable_any/53830.cc
@@ -0,0 +1,68 @@
+// { dg-do run { target *-*-freebsd* *-*-netbsd* *-*-linux* *-*-solaris* *-*-cygwin *-*-darwin* powerpc-ibm-aix* } }
+// { dg-options " -std=gnu++0x -pthread" { target *-*-freebsd* *-*-netbsd* *-*-linux* powerpc-ibm-aix* } }
+// { dg-options " -std=gnu++0x -pthreads" { target *-*-solaris* } }
+// { dg-options " -std=gnu++0x " { target *-*-cygwin *-*-darwin* } }
+// { dg-require-cstdint "" }
+// { dg-require-gthreads "" }
+// { dg-require-sched-yield "" }
+// { dg-require-nanosleep "" }
+
+// Copyright (C) 2012 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// PR libstdc++/53830
+// Test for deadlock in condition_variable_any::wait_for
+
+#include <thread>
+#include <mutex>
+#include <condition_variable>
+#include <chrono>
+#include <atomic>
+
+std::mutex mutex;
+std::condition_variable_any cv;
+
+std::atomic<int> barrier(0);
+
+// waits for data from another thread
+void wait_for_data()
+{
+  std::unique_lock<std::mutex> lock(mutex);
+  barrier = 1;
+  cv.wait_for(lock, std::chrono::milliseconds(100), []{ return false; });
+  // read data
+}
+
+// passes data to waiting thread
+void provide_data()
+{
+  while (barrier == 0)
+    std::this_thread::yield();
+  std::unique_lock<std::mutex> lock(mutex);
+  // pass data
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+  cv.notify_one();
+}
+
+int main()
+{
+  std::thread thread1(wait_for_data);
+  provide_data();
+  thread1.join();
+  return 0;
+}
+
-- 
2.47.2