diff --git a/src/add-ons/kernel/network/stack/interfaces.cpp b/src/add-ons/kernel/network/stack/interfaces.cpp
index 62268c9154..60e4a0175c 100644
--- a/src/add-ons/kernel/network/stack/interfaces.cpp
+++ b/src/add-ons/kernel/network/stack/interfaces.cpp
@@ -1209,6 +1209,8 @@ find_interface(const char* name)
 static Interface*
 find_interface(uint32 index)
 {
+	ASSERT_LOCKED_RECURSIVE(&sLock);
+
 	InterfaceList::Iterator iterator = sInterfaces.GetIterator();
 	while (Interface* interface = iterator.Next()) {
 		if (interface->index == index)