diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 3b91e6a..6a39a21 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -130,8 +130,13 @@
  */
 #define PTHREAD_STACK_SIZE_DEFAULT ((1 * 1024 * 1024) - SIGSTKSZ)
 
-/* Leave room for a guard page in the internally created signal stacks. */
+// Leave room for a guard page in the internally created signal stacks.
+#if defined(__LP64__)
+// SIGSTKSZ is not big enough for 64-bit arch. See http://b/23041777.
+#define SIGNAL_STACK_SIZE (16 * 1024 + PAGE_SIZE)
+#else
 #define SIGNAL_STACK_SIZE (SIGSTKSZ + PAGE_SIZE)
+#endif
 
 /* Needed by fork. */
 __LIBC_HIDDEN__ extern void __bionic_atfork_run_prepare();