From 36eade7f4ccf5a7da8e9f5e7ec32d2e4f8660e85 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Wed, 26 Aug 2020 01:45:51 +0000
Subject: [PATCH] hle/kernel: Fix data race in GetCurrentHostThreadID

As reported by tsan, host_thread_ids could be read while
any of the RegisterHostThread variants were called.

To fix this, lock the register mutex when yuzu is running in multicore
mode and GetCurrentHostThreadID is called.
---
 src/core/hle/kernel/kernel.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/core/hle/kernel/kernel.cpp b/src/core/hle/kernel/kernel.cpp
index cabe8d4187..f2b0fe2fdf 100644
--- a/src/core/hle/kernel/kernel.cpp
+++ b/src/core/hle/kernel/kernel.cpp
@@ -219,6 +219,7 @@ struct KernelCore::Impl {
                 return static_cast<u32>(system.GetCpuManager().CurrentCore());
             }
         }
+        std::unique_lock lock{register_thread_mutex};
         const auto it = host_thread_ids.find(this_id);
         if (it == host_thread_ids.end()) {
             return Core::INVALID_HOST_THREAD_ID;
@@ -324,7 +325,7 @@ struct KernelCore::Impl {
     std::unordered_map<std::thread::id, u32> host_thread_ids;
     u32 registered_thread_ids{Core::Hardware::NUM_CPU_CORES};
     std::bitset<Core::Hardware::NUM_CPU_CORES> registered_core_threads;
-    std::mutex register_thread_mutex;
+    mutable std::mutex register_thread_mutex;
 
     // Kernel memory management
     std::unique_ptr<Memory::MemoryManager> memory_manager;