diff --git a/sources/context_stack.c b/sources/context_stack.c
index 2217cea2..a47313fe 100644
--- a/sources/context_stack.c
+++ b/sources/context_stack.c
@@ -23,6 +23,7 @@ int mm_contextstack_create(mm_contextstack_t *stack, size_t size, size_t size_gu
 	base += size_guard;
 	stack->pointer = base;
 	stack->size = size;
+	stack->size_guard = size_guard;
 #ifdef HAVE_VALGRIND
 	stack->valgrind_stack =
 		VALGRIND_STACK_REGISTER(stack->pointer, stack->pointer + stack->size);