diff --git a/options/posix/generic/pthread-stubs.cpp b/options/posix/generic/pthread-stubs.cpp
index 7c60cc2900..cc3a49294d 100644
--- a/options/posix/generic/pthread-stubs.cpp
+++ b/options/posix/generic/pthread-stubs.cpp
@@ -354,11 +354,18 @@ namespace {
 	FutexLock key_mutex_;
 }
 
-int pthread_exit(void *ret_val) {
+namespace mlibc {
+	[[noreturn]] void do_exit() {
+		sys_thread_exit();
+		__builtin_unreachable();
+	}
+}
+
+[[noreturn]] void pthread_exit(void *ret_val) {
 	auto self = mlibc::get_current_tcb();
 
 	if (__atomic_load_n(&self->cancelBits, __ATOMIC_RELAXED) & tcbExitingBit)
-		return 0; // We are already exiting
+		mlibc::do_exit();
 
 	__atomic_fetch_or(&self->cancelBits, tcbExitingBit, __ATOMIC_RELAXED);
 
@@ -392,8 +399,7 @@ int pthread_exit(void *ret_val) {
 	// TODO: clean up thread resources when we are detached.
 
 	// TODO: do exit(0) when we're the only thread instead
-	mlibc::sys_thread_exit();
-	__builtin_unreachable();
+	mlibc::do_exit();
 }
 
 int pthread_join(pthread_t thread, void **ret) {
diff --git a/options/posix/include/pthread.h b/options/posix/include/pthread.h
index 87deb2966b..701e2fd8dc 100644
--- a/options/posix/include/pthread.h
+++ b/options/posix/include/pthread.h
@@ -179,7 +179,7 @@ int pthread_create(pthread_t *__restrict, const pthread_attr_t *__restrict,
 		void *(*) (void *), void *__restrict);
 pthread_t pthread_self(void);
 int pthread_equal(pthread_t, pthread_t);
-int pthread_exit(void *);
+[[noreturn]] void pthread_exit(void *);
 
 int pthread_join(pthread_t, void **);
 int pthread_detach(pthread_t);