diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
index 974189da8a91..dba28755d284 100644
--- a/tools/bpf/bpftool/net.c
+++ b/tools/bpf/bpftool/net.c
@@ -603,14 +603,14 @@ static int query_flow_dissector(struct bpf_attach_info *attach_info)
 			     &attach_flags, prog_ids, &prog_cnt);
 	close(fd);
 	if (err) {
-		if (errno == EINVAL) {
+		if (err == -EINVAL) {
 			/* Older kernel's don't support querying
 			 * flow dissector programs.
 			 */
 			errno = 0;
 			return 0;
 		}
-		p_err("can't query prog: %s", strerror(errno));
+		p_err("can't query prog: %s", strerror(-err));
 		return -1;
 	}