[llvm] [BOLT] Fix thread-safety of MarkRAStates (PR #165368)

[Gergely Bálint via llvm-commits]

https://github.com/bgergely0 created https://github.com/llvm/llvm-project/pull/165368

The pass calls setIgnored() on functions in parallel, but setIgnored is
not thread safe. The patch adds a mutex to guard setIgnored calls.

Fixes: #165362

>From e29e1ab06e3570cf6c76634f8954b4c381fbbb33 Mon Sep 17 00:00:00 2001
From: Gergely Balint <gergely.balint at arm.com>
Date: Tue, 28 Oct 2025 09:15:35 +0000
Subject: [PATCH] [BOLT] Fix thread-safety of MarkRAStates

The pass calls setIgnored() on functions in parallel, but setIgnored is
not thread safe. The patch adds a mutex to guard setIgnored calls.

Fixes: #165362
---
 bolt/include/bolt/Passes/MarkRAStates.h | 5 +++++
 bolt/lib/Passes/MarkRAStates.cpp        | 3 +++
 2 files changed, 8 insertions(+)

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..edef5d88aec62 100644
--- a/bolt/lib/Passes/MarkRAStates.cpp
+++ b/bolt/lib/Passes/MarkRAStates.cpp
@@ -43,6 +43,7 @@ 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.
+        std::lock_guard<std::mutex> Lock(IgnoreMutex);
         BF.setIgnored();
         BC.outs() << "BOLT-INFO: inconsistent RAStates in function "
                   << BF.getPrintName()
@@ -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;
         }