diff --git a/bolt/include/bolt/Passes/MarkRAStates.h b/bolt/include/bolt/Passes/MarkRAStates.h
index 675ab9727142b..202f1dda2aad8 100644
--- a/bolt/include/bolt/Passes/MarkRAStates.h
+++ b/bolt/include/bolt/Passes/MarkRAStates.h
@@ -13,11 +13,16 @@
 #define BOLT_PASSES_MARK_RA_STATES
 
 #include "bolt/Passes/BinaryPasses.h"
+#include <mutex>
 
 namespace llvm {
 namespace bolt {
 
 class MarkRAStates : public BinaryFunctionPass {
+  // setIgnored() is not thread-safe, but the pass is running on functions in
+  // parallel.
+  std::mutex IgnoreMutex;
+
 public:
   explicit MarkRAStates() : BinaryFunctionPass(false) {}
 
diff --git a/bolt/lib/Passes/MarkRAStates.cpp b/bolt/lib/Passes/MarkRAStates.cpp
index af6a5ca7e31e5..b262d66732b7d 100644
--- a/bolt/lib/Passes/MarkRAStates.cpp
+++ b/bolt/lib/Passes/MarkRAStates.cpp
@@ -43,10 +43,11 @@ bool MarkRAStates::runOnFunction(BinaryFunction &BF) {
         // Not all functions have .cfi_negate_ra_state in them. But if one does,
         // we expect psign/pauth instructions to have the hasNegateRAState
         // annotation.
-        BF.setIgnored();
         BC.outs() << "BOLT-INFO: inconsistent RAStates in function "
                   << BF.getPrintName()
                   << ": ptr sign/auth inst without .cfi_negate_ra_state\n";
+        std::lock_guard<std::mutex> Lock(IgnoreMutex);
+        BF.setIgnored();
         return false;
       }
     }
@@ -67,6 +68,7 @@ bool MarkRAStates::runOnFunction(BinaryFunction &BF) {
           BC.outs() << "BOLT-INFO: inconsistent RAStates in function "
                     << BF.getPrintName()
                     << ": ptr signing inst encountered in Signed RA state\n";
+          std::lock_guard<std::mutex> Lock(IgnoreMutex);
           BF.setIgnored();
           return false;
         }
@@ -80,6 +82,7 @@ bool MarkRAStates::runOnFunction(BinaryFunction &BF) {
                     << BF.getPrintName()
                     << ": ptr authenticating inst encountered in Unsigned RA "
                        "state\n";
+          std::lock_guard<std::mutex> Lock(IgnoreMutex);
           BF.setIgnored();
           return false;
         }