diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index fb4acc2f4bd4..dad254c20fb9 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2015-12-16  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/68921
+	* src/c++11/futex.cc
+	(__atomic_futex_unsigned_base::_M_futex_wait_until): Use null pointer
+	as timeout argument.
+
 2015-12-15  Tim Shen  <timshen@google.com>
 
 	Backport from mainline
diff --git a/libstdc++-v3/src/c++11/futex.cc b/libstdc++-v3/src/c++11/futex.cc
index e04dba812bf0..e723364ced08 100644
--- a/libstdc++-v3/src/c++11/futex.cc
+++ b/libstdc++-v3/src/c++11/futex.cc
@@ -52,7 +52,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	// we will fall back to spin-waiting.  The only thing we could do
 	// here on errors is abort.
 	int ret __attribute__((unused));
-	ret = syscall (SYS_futex, __addr, futex_wait_op, __val);
+	ret = syscall (SYS_futex, __addr, futex_wait_op, __val, nullptr);
 	_GLIBCXX_DEBUG_ASSERT(ret == 0 || errno == EINTR || errno == EAGAIN);
 	return true;
       }