diff --git a/debian/templates/image.plain.postinst.in b/debian/templates/image.plain.postinst.in
index a6f00bc7a..439d4b872 100755
--- a/debian/templates/image.plain.postinst.in
+++ b/debian/templates/image.plain.postinst.in
@@ -551,9 +551,8 @@ else {
 # of / are the same as that of /sbin/init. This may fail if not running as
 # root or if /proc is not mounted, in which case 2 is returned.
 sub detect_chroot {
-  my $dev1, $ino1, $dev2, $ino2;
-  ($dev1, $ino1) = stat("/") or return 2;
-  ($dev2, $ino2) = stat("/proc/1/root") or return 2;
+  my ($dev1, $ino1) = stat("/") or return 2;
+  my ($dev2, $ino2) = stat("/proc/1/root") or return 2;
   return ($dev1 != $dev2) || ($ino1 != $ino2);
 }