diff --git a/tshark.c b/tshark.c
index 00c28db781..e02b61b663 100644
--- a/tshark.c
+++ b/tshark.c
@@ -1977,10 +1977,10 @@ real_main(int argc, char *argv[])
       /* Activate the export PDU tap */
       comment = g_strdup_printf("Dump of PDUs from %s", cf_name);
       err = exp_pdu_open(&exp_pdu_tap_data, exp_fd, comment);
+      g_free(comment);
       if (err != 0) {
           cfile_dump_open_failure_message("TShark", exp_pdu_filename, err,
                                           WTAP_FILE_TYPE_SUBTYPE_PCAPNG);
-          g_free(comment);
           exit_status = INVALID_EXPORT;
           goto clean_exit;
       }
diff --git a/ui/export_pdu_ui_utils.c b/ui/export_pdu_ui_utils.c
index a567a61991..c9e40b7a24 100644
--- a/ui/export_pdu_ui_utils.c
+++ b/ui/export_pdu_ui_utils.c
@@ -43,8 +43,8 @@ exp_pdu_file_open(exp_pdu_t *exp_pdu_tap_data)
 
     comment = g_strdup_printf("Dump of PDUs from %s", cfile.filename);
     err = exp_pdu_open(exp_pdu_tap_data, import_file_fd, comment);
+    g_free(comment);
     if (err != 0) {
-        g_free(comment);
         cfile_dump_open_failure_alert_box(capfile_name ? capfile_name : "temporary file",
                                           err, WTAP_FILE_TYPE_SUBTYPE_PCAPNG);
         goto end;
diff --git a/ui/tap_export_pdu.c b/ui/tap_export_pdu.c
index 25232f0452..d3302a5aca 100644
--- a/ui/tap_export_pdu.c
+++ b/ui/tap_export_pdu.c
@@ -82,7 +82,7 @@ export_pdu_packet(void *tapdata, packet_info *pinfo, epan_dissect_t *edt, const
 }
 
 int
-exp_pdu_open(exp_pdu_t *exp_pdu_tap_data, int fd, char *comment)
+exp_pdu_open(exp_pdu_t *exp_pdu_tap_data, int fd, const char *comment)
 {
 
     int   err;
@@ -103,7 +103,6 @@ exp_pdu_open(exp_pdu_t *exp_pdu_tap_data, int fd, char *comment)
 
     /* options */
     wtap_block_add_string_option(shb_hdr, OPT_COMMENT, comment, strlen(comment));
-    g_free(comment);
 
     /*
      * UTF-8 string containing the name of the operating system used to create
diff --git a/ui/tap_export_pdu.h b/ui/tap_export_pdu.h
index ea5c4077e1..9ae2dea65f 100644
--- a/ui/tap_export_pdu.h
+++ b/ui/tap_export_pdu.h
@@ -41,7 +41,7 @@ char *exp_pdu_pre_open(const char *tap_name, const char *filter,
 *
 * @return 0 on success or a wtap error code.
 */
-int exp_pdu_open(exp_pdu_t *data, int fd, char *comment);
+int exp_pdu_open(exp_pdu_t *data, int fd, const char *comment);
 
 /* Stops the PDUs export. */
 int exp_pdu_close(exp_pdu_t *exp_pdu_tap_data);
diff --git a/ui/cli/tap-wspstat.c b/ui/cli/tap-wspstat.c
index 22862cdaf8..fd6f3ad427 100644
--- a/ui/cli/tap-wspstat.c
+++ b/ui/cli/tap-wspstat.c
@@ -252,9 +252,9 @@ wspstat_init(const char *opt_arg, void *userdata _U_)
 		/* error, we failed to attach to the tap. clean up */
 		g_free(sp->pdu_stats);
 		g_free(sp->filter);
-		g_free(sp);
 		g_hash_table_foreach( sp->hash, (GHFunc) wsp_free_hash_table, NULL ) ;
 		g_hash_table_destroy( sp->hash );
+		g_free(sp);
 		fprintf(stderr, "tshark: Couldn't register wsp,stat tap: %s\n",
 				error_string->str);
 		g_string_free(error_string, TRUE);
diff --git a/epan/dissectors/packet-isobus-vt.c b/epan/dissectors/packet-isobus-vt.c
index 1f9fa98..79f1c1f 100644
--- a/epan/dissectors/packet-isobus-vt.c
+++ b/epan/dissectors/packet-isobus-vt.c
@@ -1546,16 +1546,8 @@ dissect_vt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, enum vt_directio
             }
             else
             {
-                if(status == 0)
-                {
-                    col_append_fstr(pinfo->cinfo, COL_INFO, "Status of Auxiliary Input %s was successfully changed to enabled",
-                        get_object_id_string(auxiliary_input_object_id));
-                }
-                else
-                {
-                    col_append_fstr(pinfo->cinfo, COL_INFO, "Status of Auxiliary Input %s was successfully changed to enabled",
-                        get_object_id_string(auxiliary_input_object_id));
-                }
+                col_append_fstr(pinfo->cinfo, COL_INFO, "Status of Auxiliary Input %s was successfully changed to enabled",
+                    get_object_id_string(auxiliary_input_object_id));
             }
         }
     }
diff --git a/epan/dfilter/dfilter.c b/epan/dfilter/dfilter.c
index a975f84..3e440b3 100644
--- a/epan/dfilter/dfilter.c
+++ b/epan/dfilter/dfilter.c
@@ -221,6 +221,7 @@ dfilter_compile(const gchar *text, dfilter_t **dfp, gchar **err_msg)
 	}
 
 	if ( !( expanded_text = dfilter_macro_apply(text, err_msg) ) ) {
+		*dfp = NULL;
 		return FALSE;
 	}