diff --git a/pkgs/by-name/rt/rt-tests/package.nix b/pkgs/by-name/rt/rt-tests/package.nix
index c9f78c1fe6bd..6d0b3036e094 100644
--- a/pkgs/by-name/rt/rt-tests/package.nix
+++ b/pkgs/by-name/rt/rt-tests/package.nix
@@ -9,13 +9,15 @@
 
 stdenv.mkDerivation rec {
   pname = "rt-tests";
-  version = "2.8";
+  version = "2.9";
 
   src = fetchurl {
     url = "https://git.kernel.org/pub/scm/utils/rt-tests/rt-tests.git/snapshot/${pname}-${version}.tar.gz";
-    sha256 = "sha256-iBpd7K9VpvUH5wXBKypyQl8NAHN3Om5/PcoJ8RH37mI=";
+    sha256 = "sha256-Zmb0RqGvS4bHy+6Krs3of1WUWOqJMOH0FHAXIqlteys=";
   };
 
+  env.NIX_CFLAGS_COMPILE = "-Wno-error=format-overflow";
+
   nativeBuildInputs = [ makeWrapper ];
   buildInputs = [
     numactl