memleak: don't require a root pointer.

We can just track everything from NULL (the ultimate parent) down.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/memleak.c

@@ -247,14 +247,22 @@ static void add_backtrace(tal_t *parent UNUSED, enum tal_notify_type type UNNEED
 	tal_add_notifier(child, TAL_NOTIFY_ADD_CHILD, add_backtrace);
 }
 
-void memleak_init(const tal_t *root)
+static void add_backtrace_notifiers(const tal_t *root)
+{
+	tal_add_notifier(root, TAL_NOTIFY_ADD_CHILD, add_backtrace);
+
+	for (tal_t *i = tal_first(root); i; i = tal_next(i))
+		add_backtrace_notifiers(i);
+}
+
+void memleak_init(void)
 {
 	assert(!notleaks);
 	notleaks = tal_arr(NULL, const void *, 0);
 	notleak_children = tal_arr(notleaks, bool, 0);
 
 	if (backtrace_state)
-		tal_add_notifier(root, TAL_NOTIFY_ADD_CHILD, add_backtrace);
+		add_backtrace_notifiers(NULL);
 }
 
 void memleak_cleanup(void)

common/memleak.h

@@ -22,8 +22,8 @@ void *notleak_(const void *ptr, bool plus_children);
 
 struct htable;
 
-/* Initialize memleak detection, with this as the root */
-void memleak_init(const tal_t *root);
+/* Initialize memleak detection */
+void memleak_init(void);
 
 /* Free memleak detection. */
 void memleak_cleanup(void);

lightningd/lightningd.c

@@ -54,7 +54,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->dev_allow_localhost = false;
 
 	if (getenv("LIGHTNINGD_DEV_MEMLEAK"))
-		memleak_init(ld);
+		memleak_init();
 #endif
 
 	list_head_init(&ld->peers);