src/hotspot/share/runtime/basicLock.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.

*** 22,31 ****
--- 22,32 ----
   *
   */
  
  #include "precompiled.hpp"
  #include "runtime/basicLock.hpp"
+ #include "runtime/objectMonitor.hpp"
  #include "runtime/synchronizer.hpp"
  
  void BasicLock::print_on(outputStream* st) const {
    st->print("monitor");
    markWord mark_word = displaced_header();
*** 60,71 ****
    // we need to ensure that both locations refer to the current thread's stack.
    // There are some subtle concurrency issues, however, and since the benefit is
    // is small (given the support for inflated fast-path locking in the fast_lock, etc)
    // we'll leave that optimization for another time.
  
    if (displaced_header().is_neutral()) {
!     ObjectSynchronizer::inflate_helper(obj);
      // WARNING: We can not put check here, because the inflation
      // will not update the displaced header. Once BasicLock is inflated,
      // no one should ever look at its content.
    } else {
      // Typically the displaced header will be 0 (recursive stack lock) or
--- 61,75 ----
    // we need to ensure that both locations refer to the current thread's stack.
    // There are some subtle concurrency issues, however, and since the benefit is
    // is small (given the support for inflated fast-path locking in the fast_lock, etc)
    // we'll leave that optimization for another time.
  
+   // Disallow async deflation of the inflated monitor so the
+   // displaced header stays stable until we've copied it.
+   ObjectMonitorHandle omh;
    if (displaced_header().is_neutral()) {
!     ObjectSynchronizer::inflate_helper(&omh, obj);
      // WARNING: We can not put check here, because the inflation
      // will not update the displaced header. Once BasicLock is inflated,
      // no one should ever look at its content.
    } else {
      // Typically the displaced header will be 0 (recursive stack lock) or