[Lldb-commits] [lldb] fef609d - Revert "[lldb] Fix data race in ThreadList"

[Augusto Noronha via lldb-commits]

Author: Augusto Noronha
Date: 2023-08-22T11:14:04-07:00
New Revision: fef609d2d1da573150121a6ee897e1d90f235eb1

URL: https://github.com/llvm/llvm-project/commit/fef609d2d1da573150121a6ee897e1d90f235eb1
DIFF: https://github.com/llvm/llvm-project/commit/fef609d2d1da573150121a6ee897e1d90f235eb1.diff

LOG: Revert "[lldb] Fix data race in ThreadList"

This reverts commit bb90063249707e3ae081bfbd8e3512566abb7df6.

Added: 
    

Modified: 
    lldb/include/lldb/Target/Process.h
    lldb/include/lldb/Target/ThreadCollection.h
    lldb/include/lldb/Target/ThreadList.h
    lldb/source/Target/Process.cpp
    lldb/source/Target/ThreadList.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/include/lldb/Target/Process.h b/lldb/include/lldb/Target/Process.h
index 8e75ed85229429..44cda6d2ce1aad 100644
--- a/lldb/include/lldb/Target/Process.h
+++ b/lldb/include/lldb/Target/Process.h
@@ -2970,6 +2970,7 @@ void PruneThreadPlans();
   std::string m_exit_string; ///< A textual description of why a process exited.
   std::mutex m_exit_status_mutex; ///< Mutex so m_exit_status m_exit_string can
                                   ///be safely accessed from multiple threads
+  std::recursive_mutex m_thread_mutex;
   ThreadList m_thread_list_real; ///< The threads for this process as are known
                                  ///to the protocol we are debugging with
   ThreadList m_thread_list; ///< The threads for this process as the user will

diff  --git a/lldb/include/lldb/Target/ThreadCollection.h b/lldb/include/lldb/Target/ThreadCollection.h
index dc7d8f13eee037..29f5103e7eec7c 100644
--- a/lldb/include/lldb/Target/ThreadCollection.h
+++ b/lldb/include/lldb/Target/ThreadCollection.h
@@ -47,7 +47,7 @@ class ThreadCollection {
     return ThreadIterable(m_threads, GetMutex());
   }
 
-  std::recursive_mutex &GetMutex() const { return m_mutex; }
+  virtual std::recursive_mutex &GetMutex() const { return m_mutex; }
 
 protected:
   collection m_threads;

diff  --git a/lldb/include/lldb/Target/ThreadList.h b/lldb/include/lldb/Target/ThreadList.h
index 8aaff6e4cba0d4..6af04f8ffc3767 100644
--- a/lldb/include/lldb/Target/ThreadList.h
+++ b/lldb/include/lldb/Target/ThreadList.h
@@ -133,6 +133,8 @@ class ThreadList : public ThreadCollection {
 
   void SetStopID(uint32_t stop_id);
 
+  std::recursive_mutex &GetMutex() const override;
+
   void Update(ThreadList &rhs);
 
 protected:

diff  --git a/lldb/source/Target/Process.cpp b/lldb/source/Target/Process.cpp
index 57864a8a5da922..85ca0f6ab8d153 100644
--- a/lldb/source/Target/Process.cpp
+++ b/lldb/source/Target/Process.cpp
@@ -435,7 +435,7 @@ Process::Process(lldb::TargetSP target_sp, ListenerSP listener_sp,
           Listener::MakeListener("lldb.process.internal_state_listener")),
       m_mod_id(), m_process_unique_id(0), m_thread_index_id(0),
       m_thread_id_to_index_id_map(), m_exit_status(-1), m_exit_string(),
-      m_exit_status_mutex(), m_thread_list_real(this),
+      m_exit_status_mutex(), m_thread_mutex(), m_thread_list_real(this),
       m_thread_list(this), m_thread_plans(*this), m_extended_thread_list(this),
       m_extended_thread_stop_id(0), m_queue_list(this), m_queue_list_stop_id(0),
       m_notifications(), m_image_tokens(),
@@ -2455,7 +2455,7 @@ Process::WaitForProcessStopPrivate(EventSP &event_sp,
 }
 
 void Process::LoadOperatingSystemPlugin(bool flush) {
-  std::lock_guard<std::recursive_mutex> guard(GetThreadList().GetMutex());
+  std::lock_guard<std::recursive_mutex> guard(m_thread_mutex);
   if (flush)
     m_thread_list.Clear();
   m_os_up.reset(OperatingSystem::FindPlugin(this, nullptr));

diff  --git a/lldb/source/Target/ThreadList.cpp b/lldb/source/Target/ThreadList.cpp
index fc6cbd48cf8653..1ba0c435b993d3 100644
--- a/lldb/source/Target/ThreadList.cpp
+++ b/lldb/source/Target/ThreadList.cpp
@@ -736,8 +736,7 @@ void ThreadList::Update(ThreadList &rhs) {
   if (this != &rhs) {
     // Lock both mutexes to make sure neither side changes anyone on us while
     // the assignment occurs
-    std::scoped_lock<std::recursive_mutex, std::recursive_mutex> guard(
-        GetMutex(), rhs.GetMutex());
+    std::scoped_lock<std::recursive_mutex, std::recursive_mutex> guard(GetMutex(), rhs.GetMutex());
 
     m_process = rhs.m_process;
     m_stop_id = rhs.m_stop_id;
@@ -782,6 +781,10 @@ void ThreadList::Flush() {
     (*pos)->Flush();
 }
 
+std::recursive_mutex &ThreadList::GetMutex() const {
+  return m_process->m_thread_mutex;
+}
+
 ThreadList::ExpressionExecutionThreadPusher::ExpressionExecutionThreadPusher(
     lldb::ThreadSP thread_sp)
     : m_thread_list(nullptr), m_tid(LLDB_INVALID_THREAD_ID) {