bugfix: fixed memory leak in debug log.

Author: hawkxiang

src/ngx_stream_lua_logby.c

@@ -77,6 +77,9 @@ ngx_stream_lua_log_handler(ngx_stream_session_t *r)
 #if (NGX_STREAM_LUA_HAVE_MALLOC_TRIM)
     ngx_uint_t                           trim_cycle, trim_nreq;
     ngx_stream_lua_main_conf_t          *lmcf;
+#if (NGX_DEBUG)
+    ngx_int_t                            trim_ret;
+#endif
 #endif
     ngx_stream_lua_loc_conf_t           *llcf;
     ngx_stream_lua_ctx_t                *ctx;
@@ -96,8 +99,9 @@ ngx_stream_lua_log_handler(ngx_stream_session_t *r)
             lmcf->malloc_trim_req_count = 0;
 
 #if (NGX_DEBUG)
+            trim_ret = malloc_trim(1);
             ngx_log_debug1(NGX_LOG_DEBUG_STREAM, r->connection->log, 0,
-                           "malloc_trim(1) returned %d", malloc_trim(1));
+                           "malloc_trim(1) returned %d", trim_ret);
 #else
             (void) malloc_trim(1);
 #endif