diff --git a/src/or/hibernate.c b/src/or/hibernate.c
index 979e2c31a4..0e7aa2eb93 100644
--- a/src/or/hibernate.c
+++ b/src/or/hibernate.c
@@ -411,6 +411,9 @@ accounting_run_housekeeping(time_t now)
   if (time_to_record_bandwidth_usage(now)) {
     if (accounting_record_bandwidth_usage(now)) {
       log_fn(LOG_ERR, "Couldn't record bandwidth usage; exiting.");
+      /* XXX this can fail when you're out of fd's, causing a crash.
+       * Perhaps the better answer is to hold the file open all the
+       * time? */
       exit(1);
     }
   }