nixpkgs/pkgs/os-specific/linux/powertop/auto-tune.patch

diff --git a/src/devices/devfreq.cpp b/src/devices/devfreq.cpp
index d2e56e3..4de5c9b 100644
--- a/src/devices/devfreq.cpp
+++ b/src/devices/devfreq.cpp
@@ -247,6 +247,7 @@ void create_all_devfreq_devices(void)
 		fprintf(stderr, "Devfreq not enabled\n");
 		is_enabled = false;
 		closedir(dir);
+		dir = NULL;
 		return;
 	}