diff -Nru ifupdown-0.7.2ubuntu3/debian/changelog ifupdown-0.7.2ubuntu4/debian/changelog
--- ifupdown-0.7.2ubuntu3/debian/changelog	2013-09-11 18:22:11.000000000 -0500
+++ ifupdown-0.7.2ubuntu4/debian/changelog	2013-09-16 11:37:22.000000000 -0500
@@ -1,3 +1,11 @@
+ifupdown (0.7.2ubuntu4) quantal; urgency=low
+
+  * Backport a fix from upstream mercurial
+    (http://anonscm.debian.org/hg/collab-maint/ifupdown/rev/fb3055c2c4f0)
+    for a regression introduced by a93db3ecb8f0. LP: #1226067
+
+ -- Chris J Arges <chris.j.arges@canonical.com>  Mon, 16 Sep 2013 11:37:22 -0500
+
 ifupdown (0.7.2ubuntu3) quantal; urgency=low
 
   * Backport a fix from upstream mercurial
diff -Nru ifupdown-0.7.2ubuntu3/ifupdown.nw ifupdown-0.7.2ubuntu4/ifupdown.nw
--- ifupdown-0.7.2ubuntu3/ifupdown.nw	2013-09-11 18:21:51.000000000 -0500
+++ ifupdown-0.7.2ubuntu4/ifupdown.nw	2013-09-16 11:37:22.000000000 -0500
@@ -4422,8 +4422,10 @@
 	}
 
 	if (lock_fd(fileno(lock_fp)) < 0) {
-		fprintf(stderr, "%s: failed to lock lockfile %s: %s\n", argv0, lockfile, strerror(errno));
-		exit(1);
+		if (!no_act) {
+			fprintf(stderr, "%s: failed to lock lockfile %s: %s\n", argv0, lockfile, strerror(errno));
+			exit(1);
+		}
 	}
 
 	return lock_fp;