Index: include/lldb/Target/Process.h
===================================================================
--- include/lldb/Target/Process.h
+++ include/lldb/Target/Process.h
@@ -2701,6 +2701,7 @@
   bool m_should_detach; /// Should we detach if the process object goes away
                         /// with an explicit call to Kill or Detach?
   LanguageRuntimeCollection m_language_runtimes;
+  std::recursive_mutex m_language_runtimes_mutex;
   InstrumentationRuntimeCollection m_instrumentation_runtimes;
   std::unique_ptr<NextEventAction> m_next_event_action_up;
   std::vector<PreResumeCallbackAndBaton> m_pre_resume_actions;
Index: source/Target/Process.cpp
===================================================================
--- source/Target/Process.cpp
+++ source/Target/Process.cpp
@@ -660,7 +660,9 @@
   m_image_tokens.clear();
   m_memory_cache.Clear();
   m_allocated_memory_cache.Clear();
+  m_language_runtimes_mutex.lock();
   m_language_runtimes.clear();
+  m_language_runtimes_mutex.unlock();
   m_instrumentation_runtimes.clear();
   m_next_event_action_up.reset();
   // Clear the last natural stop ID since it has a strong reference to this
@@ -1549,6 +1551,7 @@
   if (m_finalizing)
     return nullptr;
 
+  std::lock_guard<std::recursive_mutex> guard(m_language_runtimes_mutex);
   LanguageRuntimeCollection::iterator pos;
   pos = m_language_runtimes.find(language);
   if (pos == m_language_runtimes.end() || (retry_if_null && !(*pos).second)) {
@@ -1562,6 +1565,7 @@
 }
 
 CPPLanguageRuntime *Process::GetCPPLanguageRuntime(bool retry_if_null) {
+  std::lock_guard<std::recursive_mutex> guard(m_language_runtimes_mutex);
   LanguageRuntime *runtime =
       GetLanguageRuntime(eLanguageTypeC_plus_plus, retry_if_null);
   if (runtime != nullptr &&
@@ -1571,6 +1575,7 @@
 }
 
 ObjCLanguageRuntime *Process::GetObjCLanguageRuntime(bool retry_if_null) {
+  std::lock_guard<std::recursive_mutex> guard(m_language_runtimes_mutex);
   LanguageRuntime *runtime =
       GetLanguageRuntime(eLanguageTypeObjC, retry_if_null);
   if (runtime != nullptr && runtime->GetLanguageType() == eLanguageTypeObjC)
@@ -5604,7 +5609,9 @@
   m_jit_loaders_up.reset();
   m_image_tokens.clear();
   m_allocated_memory_cache.Clear();
+  m_language_runtimes_mutex.lock();
   m_language_runtimes.clear();
+  m_language_runtimes_mutex.unlock();
   m_instrumentation_runtimes.clear();
   m_thread_list.DiscardThreadPlans();
   m_memory_cache.Clear(true);
@@ -5673,6 +5680,7 @@
   // Iterate over a copy of this language runtime list in case the language
   // runtime ModulesDidLoad somehow causes the language runtime to be
   // unloaded.
+  m_language_runtimes_mutex.lock();
   LanguageRuntimeCollection language_runtimes(m_language_runtimes);
   for (const auto &pair : language_runtimes) {
     // We must check language_runtime_sp to make sure it is not nullptr as we
@@ -5682,6 +5690,7 @@
     if (language_runtime_sp)
       language_runtime_sp->ModulesDidLoad(module_list);
   }
+  m_language_runtimes_mutex.unlock();
 
   // If we don't have an operating system plug-in, try to load one since
   // loading shared libraries might cause a new one to try and load