diff --git a/pkgs/os-specific/linux/kernel/manual-config.nix b/pkgs/os-specific/linux/kernel/manual-config.nix
index 4a623fda9bec..6d1ad766d684 100644
--- a/pkgs/os-specific/linux/kernel/manual-config.nix
+++ b/pkgs/os-specific/linux/kernel/manual-config.nix
@@ -179,8 +179,7 @@ stdenv.mkDerivation ({
   configurePhase = ''
     runHook preConfigure
 
-    export buildRoot=$TMPDIR/kernel-buildroot
-    mkdir -p $buildRoot
+    export buildRoot=$(mktemp -d)
 
     echo "manual-config configurePhase buildRoot=$buildRoot pwd=$PWD"