Additional uncaught exception thrown while handling exception.

<h1>Additional uncaught exception thrown while handling exception.</h1><h2>Original</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT source FROM {url_alias} WHERE alias = :alias AND language IN (:language, :language_none) ORDER BY language DESC, pid DESC; Array
(
    [:alias] => news/269
    [:language] => zh-hans
    [:language_none] => und
)
 in drupal_lookup_path() (line 173 of /mnt/panlin/includes/path.inc).</p><h2>Additional</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT ff.*
FROM 
{filter_format} ff
WHERE  (status = :db_condition_placeholder_0) 
ORDER BY weight ASC; Array
(
    [:db_condition_placeholder_0] => 1
)
 in filter_formats() (line 434 of /mnt/panlin/modules/filter/filter.module).</p><hr />