src/hotspot/share/prims/jvmtiEnvBase.cpp

rev 57595 : v2.09a with 8235795, 8235931 and 8236035 extracted; rebased to jdk-14+28; merge with 8236035.patch.cr1; merge with 8235795.patch.cr1; merge with 8236035.patch.cr2; merge with 8235795.patch.cr2; merge with 8235795.patch.cr3.

*** 649,666 ****
  jvmtiError
  JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
  #ifdef ASSERT
    uint32_t debug_bits = 0;
  #endif
    assert((SafepointSynchronize::is_at_safepoint() ||
            java_thread->is_thread_fully_suspended(false, &debug_bits)),
           "at safepoint or target thread is suspended");
    oop obj = NULL;
!   ObjectMonitor *mon = java_thread->current_waiting_monitor();
    if (mon == NULL) {
      // thread is not doing an Object.wait() call
!     mon = java_thread->current_pending_monitor();
      if (mon != NULL) {
        // The thread is trying to enter() an ObjectMonitor.
        obj = (oop)mon->object();
        assert(obj != NULL, "ObjectMonitor should have a valid object!");
      }
--- 649,674 ----
  jvmtiError
  JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread, jobject *monitor_ptr) {
  #ifdef ASSERT
    uint32_t debug_bits = 0;
  #endif
+   // Note: The is_thread_fully_suspended() part of the assert() is
+   // from an older implementation that recognized suspension as
+   // being safe. However, that was racy in the face of rogue resumes.
+   // Should be replaced with "calling_thread == java_thread".
    assert((SafepointSynchronize::is_at_safepoint() ||
            java_thread->is_thread_fully_suspended(false, &debug_bits)),
           "at safepoint or target thread is suspended");
    oop obj = NULL;
!   // For all of the get_current_contended_monitor() call sites, we
!   // are either at a safepoint or the calling thread is operating
!   // on itself so this ObjectMonitorHandle is not strictly necessary.
!   ObjectMonitorHandle omh;
!   ObjectMonitor *mon = java_thread->current_waiting_monitor(&omh);
    if (mon == NULL) {
      // thread is not doing an Object.wait() call
!     mon = java_thread->current_pending_monitor(&omh);
      if (mon != NULL) {
        // The thread is trying to enter() an ObjectMonitor.
        obj = (oop)mon->object();
        assert(obj != NULL, "ObjectMonitor should have a valid object!");
      }
*** 732,751 ****
    }
  
    HandleMark hm;
    oop wait_obj = NULL;
    {
      // save object of current wait() call (if any) for later comparison
!     ObjectMonitor *mon = java_thread->current_waiting_monitor();
      if (mon != NULL) {
        wait_obj = (oop)mon->object();
      }
    }
    oop pending_obj = NULL;
    {
      // save object of current enter() call (if any) for later comparison
!     ObjectMonitor *mon = java_thread->current_pending_monitor();
      if (mon != NULL) {
        pending_obj = (oop)mon->object();
      }
    }
  
--- 740,767 ----
    }
  
    HandleMark hm;
    oop wait_obj = NULL;
    {
+     // For all of the get_locked_objects_in_frame() call sites, we
+     // are either at a safepoint or the calling thread is operating
+     // on itself so this ObjectMonitorHandle is not strictly necessary.
+     ObjectMonitorHandle omh;
      // save object of current wait() call (if any) for later comparison
!     ObjectMonitor *mon = java_thread->current_waiting_monitor(&omh);
      if (mon != NULL) {
        wait_obj = (oop)mon->object();
      }
    }
    oop pending_obj = NULL;
    {
+     // For all of the get_locked_objects_in_frame() call sites, we
+     // are either at a safepoint or the calling thread is operating
+     // on itself so this ObjectMonitorHandle is not strictly necessary.
+     ObjectMonitorHandle omh;
      // save object of current enter() call (if any) for later comparison
!     ObjectMonitor *mon = java_thread->current_pending_monitor(&omh);
      if (mon != NULL) {
        pending_obj = (oop)mon->object();
      }
    }