diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index a1e0c45..22cc400 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -129,6 +129,11 @@
   void* mmap_base;
   size_t mmap_size;
 
+  // The location of the VMA to label as the thread's stack_and_tls.
+  void* mmap_base_unguarded;
+  size_t mmap_size_unguarded;
+  char vma_name_buffer[32];
+
   thread_local_dtor* thread_local_dtors;
 
   /*
@@ -147,6 +152,8 @@
 struct ThreadMapping {
   char* mmap_base;
   size_t mmap_size;
+  char* mmap_base_unguarded;
+  size_t mmap_size_unguarded;
 
   char* static_tls;
   char* stack_base;
@@ -162,6 +169,7 @@
 __LIBC_HIDDEN__ void __init_additional_stacks(pthread_internal_t*);
 __LIBC_HIDDEN__ int __init_thread(pthread_internal_t* thread);
 __LIBC_HIDDEN__ ThreadMapping __allocate_thread_mapping(size_t stack_size, size_t stack_guard_size);
+__LIBC_HIDDEN__ void __set_stack_and_tls_vma_name(bool is_main_thread);
 
 __LIBC_HIDDEN__ pthread_t __pthread_internal_add(pthread_internal_t* thread);
 __LIBC_HIDDEN__ pthread_internal_t* __pthread_internal_find(pthread_t pthread_id, const char* caller);