8307067: remove broken EnableThreadSMRExtraValidityChecks option

Reviewed-by: coleenp, dholmes, sspitsyn, rehn

Author: Daniel D. Daugherty

src/hotspot/share/prims/jvmtiExport.cpp

@@ -829,8 +829,6 @@ JvmtiExport::cv_external_thread_to_JavaThread(ThreadsList * t_list,
   }
   // Looks like a live JavaThread at this point.
 
-  // We do not check the EnableThreadSMRExtraValidityChecks option
-  // for this includes() call because JVM/TI's spec is tighter.
   if (!t_list->includes(java_thread)) {
     // Not on the JavaThreads list so it is not alive.
     return JVMTI_ERROR_THREAD_NOT_ALIVE;
@@ -872,8 +870,6 @@ JvmtiExport::cv_oop_to_JavaThread(ThreadsList * t_list, oop thread_oop,
   }
   // Looks like a live JavaThread at this point.
 
-  // We do not check the EnableThreadSMRExtraValidityChecks option
-  // for this includes() call because JVM/TI's spec is tighter.
   if (!t_list->includes(java_thread)) {
     // Not on the JavaThreads list so it is not alive.
     return JVMTI_ERROR_THREAD_NOT_ALIVE;

src/hotspot/share/runtime/globals.hpp

@@ -953,9 +953,6 @@ const int ObjectAlignmentInBytes = 8;
           "null (+offset) will not raise a SIGSEGV, i.e.,"                  \
           "ImplicitNullChecks don't work (PPC64).")                         \
                                                                             \
-  product(bool, EnableThreadSMRExtraValidityChecks, true, DIAGNOSTIC,       \
-             "Enable Thread SMR extra validity checks")                     \
-                                                                            \
   product(bool, EnableThreadSMRStatistics, trueInDebug, DIAGNOSTIC,         \
              "Enable Thread SMR Statistics")                                \
                                                                             \

src/hotspot/share/runtime/threadSMR.cpp

@@ -824,10 +824,10 @@ bool ThreadsListHandle::cv_internal_thread_to_JavaThread(jobject jthread,
   // Looks like a live JavaThread at this point.
 
   if (java_thread != JavaThread::current()) {
-    // jthread is not for the current JavaThread so have to verify
-    // the JavaThread * against the ThreadsList.
-    if (EnableThreadSMRExtraValidityChecks && !includes(java_thread)) {
-      // Not on the JavaThreads list so it is not alive.
+    // java_thread is not the current JavaThread so we have to verify it
+    // against the ThreadsList.
+    if (!includes(java_thread)) {
+      // Not on this ThreadsList so it is not protected.
       return false;
     }
   }