diff --git a/pkgs/os-specific/linux/r8168/default.nix b/pkgs/os-specific/linux/r8168/default.nix
index e272449933ac..1a70c4b00332 100644
--- a/pkgs/os-specific/linux/r8168/default.nix
+++ b/pkgs/os-specific/linux/r8168/default.nix
@@ -36,10 +36,11 @@ stdenv.mkDerivation rec {
   # based on the ArchLinux pkgbuild: https://git.archlinux.org/svntogit/community.git/tree/trunk/PKGBUILD?h=packages/r8168
   makeFlags = kernelModuleMakeFlags ++ [
     "-C ${kernel.dev}/lib/modules/${kernel.modDirVersion}/build"
-    "M=$(PWD)/src"
     "modules"
   ];
   preBuild = ''
+    absSrc=$(realpath src)
+    makeFlagsArray+=("M=$absSrc")
     makeFlagsArray+=("EXTRA_CFLAGS=-DCONFIG_R8168_NAPI -DCONFIG_R8168_VLAN -DCONFIG_ASPM -DENABLE_S5WOL -DENABLE_EEE")
   '';