diff -r a6deb69743d4 -r 4cbfa5077d68 src/hotspot/os/solaris/os_solaris.cpp
--- a/src/hotspot/os/solaris/os_solaris.cpp	Mon Nov 25 12:32:07 2019 +0100
+++ b/src/hotspot/os/solaris/os_solaris.cpp	Mon Nov 25 12:32:40 2019 +0100
@@ -4797,7 +4797,7 @@
   // from the first park() call after an unpark() call which will help
   // shake out uses of park() and unpark() without condition variables.
 
-  if (Atomic::xchg(1, &_Event) >= 0) return;
+  if (Atomic::xchg(&_Event, 1) >= 0) return;
 
   // If the thread associated with the event was parked, wake it.
   // Wait for the thread assoc with the PlatformEvent to vacate.
@@ -4896,7 +4896,7 @@
   // Return immediately if a permit is available.
   // We depend on Atomic::xchg() having full barrier semantics
   // since we are doing a lock-free update to _counter.
-  if (Atomic::xchg(0, &_counter) > 0) return;
+  if (Atomic::xchg(&_counter, 0) > 0) return;
 
   // Optional fast-exit: Check interrupt before trying to wait
   Thread* thread = Thread::current();