diff --git a/net.c b/net.c
index bc0c7aa..f4a17d5 100644
--- a/net.c
+++ b/net.c
@@ -81,7 +81,11 @@ int ping_alarm (struct connection *c) {
 }
 
 void stop_ping_timer (struct connection *c) {
-  remove_event_timer (c->instance, &c->ev);
+  if (c->ev.self) {
+    remove_event_timer (c->instance, &c->ev);
+  } else {
+    warning ("trying to stop non-existing ping timer fd: #%d\n", c->fd);
+  }
 }
 
 void start_ping_timer (struct connection *c) {
diff --git a/telegram.c b/telegram.c
index 6999e9a..0bd80d3 100755
--- a/telegram.c
+++ b/telegram.c
@@ -206,9 +206,9 @@ void telegram_destroy(struct telegram *this)
     g_free(this->secret_path);
    
     // TODO: BN_CTX *ctx
-    free (this->phone_code_hash);
-    free (this->suser);
-    free (this->export_auth_str);
+    if (this->phone_code_hash) free (this->phone_code_hash);
+    if (this->suser) free (this->suser);
+    if (this->export_auth_str) free (this->export_auth_str);
     //tfree (this->ML, sizeof(struct message) * MSG_STORE_SIZE);
     tfree(this, sizeof(struct telegram));
 }