Add a mutex to the ThreadPlanStackMap class.

We've seen very occasional crashes that we can only explain by
simultaneous access to the ThreadPlanStackMap, so I'm adding a
mutex to protect it.

Differential Revision: https://reviews.llvm.org/D124029

1 files changed, 4 insertions, 0 deletions

diff --git a/lldb/source/Target/ThreadPlanStack.cpp b/lldb/source/Target/ThreadPlanStack.cpp
index 80634647f9e0..ac7b44cef37d 100644
--- a/lldb/source/Target/ThreadPlanStack.cpp
+++ b/lldb/source/Target/ThreadPlanStack.cpp
@@ -400,6 +400,7 @@ void ThreadPlanStackMap::Update(ThreadList &current_threads,
                                 bool delete_missing,
                                 bool check_for_new) {
 
+  std::lock_guard<std::recursive_mutex> guard(m_stack_map_mutex);
   // Now find all the new threads and add them to the map:
   if (check_for_new) {
     for (auto thread : current_threads.Threads()) {
@@ -434,6 +435,7 @@ void ThreadPlanStackMap::DumpPlans(Stream &strm,
                                    lldb::DescriptionLevel desc_level,
                                    bool internal, bool condense_if_trivial,
                                    bool skip_unreported) {
+  std::lock_guard<std::recursive_mutex> guard(m_stack_map_mutex);
   for (auto &elem : m_plans_list) {
     lldb::tid_t tid = elem.first;
     uint32_t index_id = 0;
@@ -470,6 +472,7 @@ bool ThreadPlanStackMap::DumpPlansForTID(Stream &strm, lldb::tid_t tid,
                                          bool internal,
                                          bool condense_if_trivial,
                                          bool skip_unreported) {
+  std::lock_guard<std::recursive_mutex> guard(m_stack_map_mutex);
   uint32_t index_id = 0;
   ThreadSP thread_sp = m_process.GetThreadList().FindThreadByID(tid);
 
@@ -509,6 +512,7 @@ bool ThreadPlanStackMap::DumpPlansForTID(Stream &strm, lldb::tid_t tid,
 
 bool ThreadPlanStackMap::PrunePlansForTID(lldb::tid_t tid) {
   // We only remove the plans for unreported TID's.
+  std::lock_guard<std::recursive_mutex> guard(m_stack_map_mutex);
   ThreadSP thread_sp = m_process.GetThreadList().FindThreadByID(tid);
   if (thread_sp)
     return false;