8253262: Allocate in DumpRegion is not thread safe

Reviewed-by: ccheung

src/hotspot/share/oops/symbol.cpp

@@ -35,6 +35,7 @@
 #include "memory/universe.hpp"
 #include "oops/symbol.hpp"
 #include "runtime/atomic.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
 #include "runtime/signature.hpp"
 #include "utilities/utf8.hpp"
@@ -63,13 +64,14 @@ Symbol::Symbol(const u1* name, int length, int refcount) {
 void* Symbol::operator new(size_t sz, int len) throw() {
 #if INCLUDE_CDS
  if (DumpSharedSpaces) {
-    // To get deterministic output from -Xshare:dump, we ensure that Symbols are allocated in
+   MutexLocker ml(DumpRegion_lock, Mutex::_no_safepoint_check_flag);
-    // increasing addresses. When the symbols are copied into the archive, we preserve their
+   // To get deterministic output from -Xshare:dump, we ensure that Symbols are allocated in
-    // relative address order (see SortedSymbolClosure in metaspaceShared.cpp)
+   // increasing addresses. When the symbols are copied into the archive, we preserve their
-    //
+   // relative address order (sorted, see ArchiveBuilder::gather_klasses_and_symbols).
-    // We cannot use arena because arena chunks are allocated by the OS. As a result, for example,
+   //
-    // the archived symbol of "java/lang/Object" may sometimes be lower than "java/lang/String", and
+   // We cannot use arena because arena chunks are allocated by the OS. As a result, for example,
-    // sometimes be higher. This would cause non-deterministic contents in the archive.
+   // the archived symbol of "java/lang/Object" may sometimes be lower than "java/lang/String", and
+   // sometimes be higher. This would cause non-deterministic contents in the archive.
    DEBUG_ONLY(static void* last = 0);
    void* p = (void*)MetaspaceShared::symbol_space_alloc(size(len)*wordSize);
    assert(p > last, "must increase monotonically");

src/hotspot/share/runtime/mutexLocker.cpp

@@ -151,6 +151,7 @@ Mutex*   CDSClassFileStream_lock      = NULL;
 #endif
 Mutex*   DumpTimeTable_lock           = NULL;
 Mutex*   CDSLambda_lock               = NULL;
+Mutex*   DumpRegion_lock              = NULL;
 #endif // INCLUDE_CDS
 
 #if INCLUDE_JVMCI
@@ -346,6 +347,7 @@ void mutex_init() {
 #endif
   def(DumpTimeTable_lock           , PaddedMutex  , leaf - 1,    true,  _safepoint_check_never);
   def(CDSLambda_lock               , PaddedMutex  , leaf,        true,  _safepoint_check_never);
+  def(DumpRegion_lock              , PaddedMutex  , leaf,        true,  _safepoint_check_never);
 #endif // INCLUDE_CDS
 
 #if INCLUDE_JVMCI

src/hotspot/share/runtime/mutexLocker.hpp

@@ -130,6 +130,7 @@ extern Mutex*   CDSClassFileStream_lock;         // FileMapInfo::open_stream_for
 #endif
 extern Mutex*   DumpTimeTable_lock;              // SystemDictionaryShared::find_or_allocate_info_for
 extern Mutex*   CDSLambda_lock;                  // SystemDictionaryShared::get_shared_lambda_proxy_class
+extern Mutex*   DumpRegion_lock;                 // Symbol::operator new(size_t sz, int len)
 #endif // INCLUDE_CDS
 #if INCLUDE_JFR
 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table