diff --git a/FU.pm b/FU.pm
index e4f4ac1..8e47c1d 100644
--- a/FU.pm
+++ b/FU.pm
@@ -491,6 +491,8 @@ sub _supervisor($c) {
             if (!$err && (!$childs{$pid} || $childs{$pid} != 2)) {
                 $err = 1;
                 log_write "Script exited before calling FU::run()\n";
+            } elsif ($?) {
+                log_write "Unclean shutdown of worker PID $pid status $?\n";
             }
             delete $childs{$pid};
         }