Revert `mutex_lock` logicbill/fix-data-races-2026-02

1 files changed, 3 insertions, 3 deletions

diff --git a/src/threading.cpp b/src/threading.cpp
index d47421a80..d8ae321f5 100644
--- a/src/threading.cpp
+++ b/src/threading.cpp
@@ -367,9 +367,9 @@ gb_internal void semaphore_wait(Semaphore *s) {
 
 	gb_internal void mutex_lock(BlockingMutex *m) {
 		ANNOTATE_LOCK_PRE(m, 0);
-		i32 expected = Internal_Mutex_State_Unlocked;
-		if (m->state().compare_exchange_strong(expected, Internal_Mutex_State_Locked, std::memory_order_acquire)) {
-			mutex_lock_slow(m, expected);
+		i32 v = m->state().exchange(Internal_Mutex_State_Locked, std::memory_order_acquire);
+		if (v != Internal_Mutex_State_Unlocked) {
+			mutex_lock_slow(m, v);
 		}
 		ANNOTATE_LOCK_POST(m);
 	}