- fix some cases where we are using uninitialized memory

runtime/vm/native_symbol_linux.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_LINUX)
 
+#include "platform/memory_sanitizer.h"
 #include "vm/native_symbol.h"
 
 #include <cxxabi.h>  // NOLINT
 #include <dlfcn.h>  // NOLINT
 
 namespace dart {
 
 void NativeSymbolResolver::InitOnce() {
 }
 
 
 void NativeSymbolResolver::ShutdownOnce() {
 }
 
 
 char* NativeSymbolResolver::LookupSymbolName(uintptr_t pc, uintptr_t* start) {
   Dl_info info;
   int r = dladdr(reinterpret_cast<void*>(pc), &info);
   if (r == 0) {
     return NULL;
   }
   if (info.dli_sname == NULL) {
     return NULL;
   }
   if (start != NULL) {
     *start = reinterpret_cast<uintptr_t>(info.dli_saddr);
   }
-  int status;
-  char* demangled = abi::__cxa_demangle(info.dli_sname, NULL, NULL, &status);
+  int status = 0;
+  size_t len = 0;
+  char* demangled = abi::__cxa_demangle(info.dli_sname, NULL, &len, &status);
+  MSAN_UNPOISON(demangled, len);
   if (status == 0) {
     return demangled;
   }
   return strdup(info.dli_sname);
 }
 
 
 void NativeSymbolResolver::FreeSymbolName(char* name) {
   free(name);
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)