diff --git a/include/my_pthread.h b/include/my_pthread.h
index 3459180b9b2..0d0e5d51bac 100644
--- a/include/my_pthread.h
+++ b/include/my_pthread.h
@@ -673,7 +673,7 @@ extern void my_mutex_end(void);
   We need to have at least 256K stack to handle calls to myisamchk_init()
   with the current number of keys and key parts.
 */
-#define DEFAULT_THREAD_STACK	(290*1024L)
+#define DEFAULT_THREAD_STACK	(291*1024L)
 #endif
 
 #define MY_PTHREAD_LOCK_READ 0