diff --git a/lib/kunit/string-stream.c b/lib/kunit/string-stream.c
index f5ae79c37400..a608746020a9 100644
--- a/lib/kunit/string-stream.c
+++ b/lib/kunit/string-stream.c
@@ -56,8 +56,8 @@ int string_stream_vadd(struct string_stream *stream,
 	frag_container = alloc_string_stream_fragment(stream->test,
 						      len,
 						      stream->gfp);
-	if (!frag_container)
-		return -ENOMEM;
+	if (IS_ERR(frag_container))
+		return PTR_ERR(frag_container);
 
 	len = vsnprintf(frag_container->fragment, len, fmt, args);
 	spin_lock(&stream->lock);
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 90640a43cf62..2a6992fe7c3e 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -265,7 +265,7 @@ static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
 	kunit_set_failure(test);
 
 	stream = alloc_string_stream(test, GFP_KERNEL);
-	if (!stream) {
+	if (IS_ERR(stream)) {
 		WARN(true,
 		     "Could not allocate stream to print failed assertion in %s:%d\n",
 		     loc->file,