diff -r 4cbfa5077d68 -r 623722a6aeb9 src/hotspot/share/jfr/leakprofiler/sampling/objectSampler.cpp
--- a/src/hotspot/share/jfr/leakprofiler/sampling/objectSampler.cpp	Mon Nov 25 12:32:40 2019 +0100
+++ b/src/hotspot/share/jfr/leakprofiler/sampling/objectSampler.cpp	Mon Nov 25 12:33:15 2019 +0100
@@ -93,7 +93,7 @@
 
 ObjectSampler* ObjectSampler::acquire() {
   assert(is_created(), "invariant");
-  while (Atomic::cmpxchg(1, &_lock, 0) == 1) {}
+  while (Atomic::cmpxchg(&_lock, 0, 1) == 1) {}
   return _instance;
 }