--- old/src/hotspot/share/runtime/os.cpp	Wed Nov  8 09:06:23 2017
+++ new/src/hotspot/share/runtime/os.cpp	Wed Nov  8 09:06:23 2017
@@ -54,6 +54,7 @@
 #include "runtime/os.inline.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/thread.inline.hpp"
+#include "runtime/threadSMR.hpp"
 #include "runtime/vm_version.hpp"
 #include "services/attachListener.hpp"
 #include "services/mallocTracker.hpp"
@@ -197,15 +198,7 @@
 }
 
 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
-#ifdef ASSERT
-  if (!(!thread->is_Java_thread() ||
-         Thread::current() == thread  ||
-         Threads_lock->owned_by_self()
-         || thread->is_Compiler_thread()
-        )) {
-    assert(false, "possibility of dangling Thread pointer");
-  }
-#endif
+  debug_only(Thread::check_for_dangling_thread_pointer(thread);)
 
   if (p >= MinPriority && p <= MaxPriority) {
     int priority = java_to_os_priority[p];
@@ -1100,7 +1093,7 @@
   }
 #endif
 
-  for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
+  for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
     // Check for privilege stack
     if (thread->privileged_stack_top() != NULL &&
         thread->privileged_stack_top()->contains(addr)) {
@@ -1126,7 +1119,6 @@
       if (verbose) thread->print_on(st);
       return;
     }
-
   }
 
   // Check if in metaspace and print types that have vptrs (only method now)
@@ -1665,7 +1657,6 @@
 }
 
 void os::SuspendedThreadTask::run() {
-  assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
   internal_do_task();
   _done = true;
 }