diff --git a/debian/changelog b/debian/changelog
index 14d9b58cd..27444d69a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -83,6 +83,7 @@ linux (4.17.3-1) UNRELEASED; urgency=medium
     (CVE-2018-12633)
   * [x86] vboxguest: Enable VBOXGUEST and DRM_VBOXVIDEO as modules
   * aufs: Update support patchset to aufs4.x-rcN-20180611
+  * debian/rules.d/scripts/mod/gendef.py: Use Python 3
 
   [ Romain Perier ]
   * [x86] amdgpu: Enable DCN 1.0 Raven family (Closes: #901349)
diff --git a/debian/rules.d/scripts/mod/Makefile b/debian/rules.d/scripts/mod/Makefile
index e57e262aa..35bf77cd2 100644
--- a/debian/rules.d/scripts/mod/Makefile
+++ b/debian/rules.d/scripts/mod/Makefile
@@ -16,7 +16,7 @@ modpost.real-%:
 	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
 modpost-opts.h: $(top_srcdir)/scripts/mod/modpost.c
-	python $(wrapperdir)/gendef.py $< > $@
+	$(wrapperdir)/gendef.py $< > $@
 
 modpost.o: modpost.c modpost-opts.h
 	$(CC) $(CFLAGS) -I $(CURDIR) -c -o $@ $<
diff --git a/debian/rules.d/scripts/mod/gendef.py b/debian/rules.d/scripts/mod/gendef.py
index 6e1bdf41b..f923d083b 100755
--- a/debian/rules.d/scripts/mod/gendef.py
+++ b/debian/rules.d/scripts/mod/gendef.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 import re
 import sys
 
@@ -10,11 +10,11 @@ for line in open(sys.argv[1]):
 else:
     raise RuntimeError
 
-print '#define GETOPT_OPTIONS "%s"' % options
+print('#define GETOPT_OPTIONS "%s"' % options)
 
-print '#define GETOPT_CASE',
+print('#define GETOPT_CASE', end=' ')
 for c in options:
     if c == ':' or c == 'T':
         continue
-    print "case '%c':" % c,
-print
+    print("case '%c':" % c, end=' ')
+print()