diff --git a/src/filters/pcre.c b/src/filters/pcre.c
index eda91a5..01846e3 100644
--- a/src/filters/pcre.c
+++ b/src/filters/pcre.c
@@ -194,6 +194,7 @@ flush(cfg_t *cfg) {
     pcre_free(r->regex);
     free(r);
   }
+  cfg->regexps = NULL;
 }
 
 void
diff --git a/src/filters/preg.c b/src/filters/preg.c
index 98afbb3..ad9fb91 100644
--- a/src/filters/preg.c
+++ b/src/filters/preg.c
@@ -159,6 +159,7 @@ flush(cfg_t *cfg) {
     regfree(&r->regex);
     free(r);
   }
+  cfg->regexps = NULL;
 }
 
 void