diff --git a/libc/bionic/__libc_init_main_thread.cpp b/libc/bionic/__libc_init_main_thread.cpp
index 56a8488..95f46e9 100644
--- a/libc/bionic/__libc_init_main_thread.cpp
+++ b/libc/bionic/__libc_init_main_thread.cpp
@@ -101,6 +101,19 @@
   __set_tcb_dtv(tcb, const_cast<TlsDtv*>(&zero_dtv));
 }
 
+// This is public so that the zygote can call it too. It is not expected
+// to be useful otherwise.
+//
+// Note in particular that it is not possible to return from any existing
+// stack frame with stack protector enabled after this function is called.
+extern "C" void android_reset_stack_guards() {
+  // The TLS stack guard is set from the global, so ensure that we've initialized the global
+  // before we initialize the TLS. Dynamic executables will initialize their copy of the global
+  // stack protector from the one in the main thread's TLS.
+  __libc_safe_arc4random_buf(&__stack_chk_guard, sizeof(__stack_chk_guard));
+  __init_tcb_stack_guard(__get_bionic_tcb());
+}
+
 // Finish initializing the main thread.
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 extern "C" void __libc_init_main_thread_late() {
@@ -119,11 +132,7 @@
   // User code should never see this; we'll compute it when asked.
   pthread_attr_setstacksize(&main_thread.attr, 0);
 
-  // The TLS stack guard is set from the global, so ensure that we've initialized the global
-  // before we initialize the TLS. Dynamic executables will initialize their copy of the global
-  // stack protector from the one in the main thread's TLS.
-  __libc_safe_arc4random_buf(&__stack_chk_guard, sizeof(__stack_chk_guard));
-  __init_tcb_stack_guard(__get_bionic_tcb());
+  android_reset_stack_guards();
 
   __init_thread(&main_thread);
 
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index e35d1fb..a224eab 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1770,4 +1770,5 @@
     android_net_res_stats_get_info_for_net;
     android_net_res_stats_aggregate;
     android_net_res_stats_get_usable_servers;
+    android_reset_stack_guards;
 } LIBC_Q;