diff --git a/common/memleak.c b/common/memleak.c
index 13e336996..03a7d96c3 100644
--- a/common/memleak.c
+++ b/common/memleak.c
@@ -256,11 +256,13 @@ struct htable *memleak_enter_allocations(const tal_t *ctx,
 	struct htable *memtable = tal(ctx, struct htable);
 	htable_init(memtable, hash_ptr, NULL);
 
-	/* First, add all pointers off NULL to table. */
-	children_into_htable(exclude1, exclude2, memtable, NULL);
+	if (memleak_track) {
+		/* First, add all pointers off NULL to table. */
+		children_into_htable(exclude1, exclude2, memtable, NULL);
 
-	/* Iterate and call helpers to eliminate hard-to-get references. */
-	call_memleak_helpers(memtable, NULL);
+		/* Iterate and call helpers to eliminate hard-to-get references. */
+		call_memleak_helpers(memtable, NULL);
+	}
 
 	tal_add_destructor(memtable, htable_clear);
 	return memtable;
diff --git a/contrib/pyln-testing/pyln/testing/utils.py b/contrib/pyln-testing/pyln/testing/utils.py
index 48b0b8a6d..be34ba7f7 100644
--- a/contrib/pyln-testing/pyln/testing/utils.py
+++ b/contrib/pyln-testing/pyln/testing/utils.py
@@ -584,11 +584,13 @@ class LightningNode(object):
             # Don't run --version on every subdaemon if we're valgrinding and slow.
             if SLOW_MACHINE and VALGRIND:
                 self.daemon.opts["dev-no-version-checks"] = None
-            self.daemon.env["LIGHTNINGD_DEV_MEMLEAK"] = "1"
             if os.getenv("DEBUG_SUBD"):
                 self.daemon.opts["dev-debugger"] = os.getenv("DEBUG_SUBD")
             if valgrind:
                 self.daemon.env["LIGHTNINGD_DEV_NO_BACKTRACE"] = "1"
+            else:
+                # Under valgrind, scanning can access uninitialized mem.
+                self.daemon.env["LIGHTNINGD_DEV_MEMLEAK"] = "1"
             if not may_reconnect:
                 self.daemon.opts["dev-no-reconnect"] = None