diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
index 14cc7da..3bfb899 100644
--- a/libc/bionic/pthread_internal.cpp
+++ b/libc/bionic/pthread_internal.cpp
@@ -34,6 +34,7 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/prctl.h>
+#include <sys/types.h>
 
 #include <async_safe/log.h>
 #include <bionic/mte.h>
@@ -78,11 +79,7 @@
 static void __pthread_internal_free(pthread_internal_t* thread) {
 #ifdef __aarch64__
   if (void* stack_mte_tls = thread->bionic_tcb->tls_slot(TLS_SLOT_STACK_MTE)) {
-    size_t size =
-        stack_mte_ringbuffer_size_from_pointer(reinterpret_cast<uintptr_t>(stack_mte_tls));
-    void* ptr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(stack_mte_tls) &
-                                        ((1ULL << 56ULL) - 1ULL));
-    munmap(ptr, size);
+    stack_mte_free_ringbuffer(reinterpret_cast<uintptr_t>(stack_mte_tls));
   }
 #endif
   if (thread->mmap_size != 0) {
diff --git a/libc/platform/bionic/mte.h b/libc/platform/bionic/mte.h
index 423ed0f..610cb45 100644
--- a/libc/platform/bionic/mte.h
+++ b/libc/platform/bionic/mte.h
@@ -117,6 +117,12 @@
   return ptr | ((1ULL << size_cls) << 56ULL);
 }
 
+inline void stack_mte_free_ringbuffer(uintptr_t stack_mte_tls) {
+  size_t size = stack_mte_ringbuffer_size_from_pointer(stack_mte_tls);
+  void* ptr = reinterpret_cast<void*>(stack_mte_tls & ((1ULL << 56ULL) - 1ULL));
+  munmap(ptr, size);
+}
+
 inline void* stack_mte_ringbuffer_allocate(size_t n, const char* name) {
   if (n > 7) return nullptr;
   // Allocation needs to be aligned to 2*size to make the fancy code-gen work.