diff --git a/libc/bionic/pthread_cond.cpp b/libc/bionic/pthread_cond.cpp
index d36426c..c35d9f1 100644
--- a/libc/bionic/pthread_cond.cpp
+++ b/libc/bionic/pthread_cond.cpp
@@ -224,16 +224,18 @@
   return pthread_cond_timedwait_monotonic(cond_interface, mutex, abs_timeout);
 }
 
+// Force this function using CLOCK_MONOTONIC because it was always using
+// CLOCK_MONOTONIC in history.
 extern "C" int pthread_cond_timedwait_relative_np(pthread_cond_t* cond_interface,
                                                   pthread_mutex_t* mutex,
                                                   const timespec* rel_timeout) {
   timespec ts;
   timespec* abs_timeout = nullptr;
   if (rel_timeout != nullptr) {
-    absolute_timespec_from_timespec(ts, *rel_timeout, CLOCK_REALTIME);
+    absolute_timespec_from_timespec(ts, *rel_timeout, CLOCK_MONOTONIC);
     abs_timeout = &ts;
   }
-  return __pthread_cond_timedwait(__get_internal_cond(cond_interface), mutex, true, abs_timeout);
+  return __pthread_cond_timedwait(__get_internal_cond(cond_interface), mutex, false, abs_timeout);
 }
 
 extern "C" int pthread_cond_timeout_np(pthread_cond_t* cond_interface,