diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 63a56ed..7f530e3 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5953,7 +5953,10 @@ struct bpf_pidns_info {
 
 /* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
 struct bpf_sk_lookup {
-	__bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
+	union {
+		__bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
+		__u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */
+	};
 
 	__u32 family;		/* Protocol family (AF_INET, AF_INET6) */
 	__u32 protocol;		/* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */