Disable r/w cbs and clear all cbs before all bufferevent_free() calls

Also, disable the events first, then clear the callbacks, for
conventional pattern.

Author: sonertari

src/protoautossl.c

@@ -84,6 +84,7 @@ protoautossl_bufferevent_free_and_close_fd(struct bufferevent *bev, pxy_conn_ctx
 		evbuffer_get_length(bufferevent_get_output(bev)), ubev ? evbuffer_get_length(bufferevent_get_output(ubev)) : 0, fd);
 
 	// @see https://stackoverflow.com/questions/31688709/knowing-all-callbacks-have-run-with-libevent-and-bufferevent-free
+	bufferevent_disable(bev, EV_READ|EV_WRITE);
 	bufferevent_setcb(bev, NULL, NULL, NULL, NULL);
 
 	/*
@@ -95,11 +96,10 @@ protoautossl_bufferevent_free_and_close_fd(struct bufferevent *bev, pxy_conn_ctx
 	SSL_set_shutdown(ssl, SSL_RECEIVED_SHUTDOWN);
 	SSL_shutdown(ssl);
 
-	bufferevent_disable(bev, EV_READ|EV_WRITE);
 	if (ubev) {
 		bufferevent_disable(ubev, EV_READ|EV_WRITE);
-		bufferevent_setfd(ubev, -1);
 		bufferevent_setcb(ubev, NULL, NULL, NULL, NULL);
+		bufferevent_setfd(ubev, -1);
 		bufferevent_free(ubev);
 	}
 	bufferevent_free(bev);

src/protossl.c

@@ -1257,6 +1257,7 @@ protossl_bufferevent_free_and_close_fd(struct bufferevent *bev, pxy_conn_ctx_t *
 	SSL_shutdown(ssl);
 
 	bufferevent_disable(bev, EV_READ|EV_WRITE);
+	bufferevent_setcb(bev, NULL, NULL, NULL, NULL);
 	bufferevent_free(bev);
 
 	if (OPTS_DEBUG(ctx->global)) {

src/prototcp.c

@@ -107,6 +107,9 @@ prototcp_bufferevent_free_and_close_fd(struct bufferevent *bev, UNUSED pxy_conn_
 
 	log_finer_va("in=%zu, out=%zu, fd=%d", evbuffer_get_length(bufferevent_get_input(bev)), evbuffer_get_length(bufferevent_get_output(bev)), fd);
 
+	bufferevent_disable(bev, EV_READ|EV_WRITE);
+	bufferevent_setcb(bev, NULL, NULL, NULL, NULL);
+
 	bufferevent_free(bev);
 	if (fd >= 0)
 		evutil_closesocket(fd);
@@ -132,8 +135,8 @@ prototcp_disable_srvdst(pxy_conn_ctx_t *ctx)
 	log_finest("ENTER");
 
 	// Do not disable underlying bevs in autossl
-	bufferevent_setcb(ctx->srvdst.bev, NULL, NULL, NULL, NULL);
 	bufferevent_disable(ctx->srvdst.bev, EV_READ|EV_WRITE);
+	bufferevent_setcb(ctx->srvdst.bev, NULL, NULL, NULL, NULL);
 
 	// Do not access srvdst.bev from this point on
 	ctx->srvdst.bev = NULL;