diff -r 9dc92e89243a -r 4aea554692aa src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp
--- a/src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp	Fri Aug 09 10:06:44 2019 +0200
+++ b/src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp	Fri Aug 09 11:04:08 2019 +0200
@@ -516,7 +516,7 @@
     elapsedTimer sample_time;
     sample_time.start();
     {
-      MutexLocker tlock(Threads_lock, Mutex::_no_safepoint_check_flag);
+      MutexLocker tlock(Threads_lock);
       ThreadsListHandle tlh;
       // Resolve a sample session relative start position index into the thread list array.
       // In cases where the last sampled thread is NULL or not-NULL but stale, find_index() returns -1.