There are a number of usages of NULL introduced in CRaC code

Below is the output of test/hotspot/jtreg/sources/TestNoNULL.java

Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/linux/crac_linux.cpp at line 277:
  if (_attach_op == NULL)
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/linux/crac_linux.cpp at line 288:
  if (_attach_op == NULL)
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/linux/os_linux.hpp at line 296:
    if (cpu_to_node() != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/posix/signals_posix.cpp at line 1546:
  const char *signal_engines[] = { "criu", "criuengine", "sim", "simengine", "pause", "pauseengine", NULL };
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/posix/signals_posix.cpp at line 1547:
  for (int i = 0; signal_engines[i] != NULL; ++i) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/posix/attachListener_posix.cpp at line 279:
  PosixAttachListener::_current_op = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/windows/os_windows.cpp at line 4732:
  if (wide_path == NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/os/windows/os_windows.cpp at line 4744:
  if (wide_path == NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/gc/g1/g1UncommitRegionTask.cpp at line 137:
  // If _instance is NULL G1 GC is either not in use or its collection has not yet been executed.
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/services/diagnosticCommand.cpp at line 1067:
  if (str != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/compiler/compileLog.cpp at line 197:
  _out = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/globals.hpp at line 1959:
  product(ccstr, CRaCCheckpointTo, NULL, RESTORE_SETTABLE, \\
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/globals.hpp at line 1962:
  product(ccstr, CRaCRestoreFrom, NULL, RESTORE_SETTABLE, \\
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/globals.hpp at line 1990:
  product(ccstr, CRaCIgnoredFileDescriptors, NULL, RESTORE_SETTABLE, \\
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 1119:
  if (equal_sign == NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 1270:
  assert(key != NULL, "key should not be NULL");
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 1271:
  assert(value != NULL, "value should not be NULL");
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 1292:
  const char* key = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 1293:
  const char* value = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 2205:
  const char *tail = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 2219:
      const char* key = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 2220:
      const char* value = NULL;
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 2227:
        if (old_java_command != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/arguments.cpp at line 2246:
      if (flag != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 48:
    _msg(NULL)
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 80:
    while (props != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 100:
    _raw_content(NULL),
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 102:
    _args(NULL)
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 137:
    while (p != NULL) {
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/share/runtime/crac_structs.hpp at line 181:
    , _attach_op(jcmd_stream ? PosixAttachListener::get_current_op() : NULL)
Error: 'NULL' found in /home/runner/work/crac/crac/src/hotspot/cpu/x86/globals_x86.hpp at line 195:
  product(ccstr, CPUFeatures, NULL, "CPU feature set, " \\
java.lang.RuntimeException: Test found 31 usages of 'NULL' in source files. See errors above.
at TestNoNULL.main(TestNoNULL.java:70)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:335)
at java.base/java.lang.Thread.run(Thread.java:1447)