diff --git a/src/udev/udevadm-test-builtin.c b/src/udev/udevadm-test-builtin.c
index 5d1fafbd03..f5498a1e5b 100644
--- a/src/udev/udevadm-test-builtin.c
+++ b/src/udev/udevadm-test-builtin.c
@@ -104,9 +104,12 @@ int builtin_main(int argc, char *argv[], void *userdata) {
         }
 
         r = udev_builtin_run(event, cmd, arg_command, true);
-        if (r < 0)
+        if (r < 0) {
                 log_debug_errno(r, "Builtin command '%s' fails: %m", arg_command);
+                goto finish;
+        }
 
+        r = 0;
 finish:
         udev_builtin_exit();
         return r;
diff --git a/src/udev/udevadm.c b/src/udev/udevadm.c
index 51dc041a29..687b927f72 100644
--- a/src/udev/udevadm.c
+++ b/src/udev/udevadm.c
@@ -137,4 +137,4 @@ static int run(int argc, char *argv[]) {
         return udevadm_main(argc, argv);
 }
 
-DEFINE_MAIN_FUNCTION(run);
+DEFINE_MAIN_FUNCTION_WITH_POSITIVE_FAILURE(run);
diff --git a/test/units/testsuite-17.10.sh b/test/units/testsuite-17.10.sh
index 20f120a930..f229dcf25f 100755
--- a/test/units/testsuite-17.10.sh
+++ b/test/units/testsuite-17.10.sh
@@ -238,4 +238,17 @@ assert_rc 124 timeout 5 udevadm wait --removed /sys/class/net/$netdev
 udevadm wait --settle /sys/class/net/$netdev
 udevadm wait -h
 
+udevadm lock --help
+udevadm lock --version
+for i in /dev/block/*; do
+    udevadm lock --device "$i" --print
+    udevadm lock --device "$i" true
+    (! udevadm lock --device "$i" false)
+done
+for i in / /usr; do
+    udevadm lock --backing "$i" --print
+    udevadm lock --backing "$i" true
+    (! udevadm lock --backing "$i" false)
+done
+
 exit 0
diff --git a/test/units/testsuite-64.sh b/test/units/testsuite-64.sh
index 81edb0ab7a..65e5f6cd91 100755
--- a/test/units/testsuite-64.sh
+++ b/test/units/testsuite-64.sh
@@ -396,6 +396,11 @@ EOF
 
     udevadm control --reload
 
+    # initialize partition table
+    for disk in {0..9}; do
+        echo 'label: gpt' | udevadm lock --device="${devices[$disk]}" sfdisk -q "${devices[$disk]}"
+    done
+
     # Delete the partitions, immediately recreate them, wait for udev to settle
     # down, and then check if we have any dangling symlinks in /dev/disk/. Rinse
     # and repeat.