WP Query Foreach具有无限循环

我需要帮助。我不知道为什么此脚本无限循环，因为我的站点现在不断冻结服务器，即将资源限制到关闭SQL Server的地步。

global $post;
$args = array(
    'posts_per_page'  => 4,
    'numberposts'     => 4,
    'offset'          => 0,
    'category'        => $id,
    'orderby'         => 'post_date',
    'order'           => 'DESC',
    'meta_key'        => '',
    'meta_value'      => '',
    'post_type'       => 'post',
    'post_mime_type'  => '',
    'post_parent'     => '',
    'post_status'     => 'publish',
    'suppress_filters' => true
);
$tips = get_posts( $args ); 
foreach( $tips as $post ) : setup_postdata($post); ?>
    <a href="<?php the_permalink(); ?>" rel="bookmark" title="<?php the_title(); ?>">
        <?php if(has_post_thumbnail()){ the_post_thumbnail( 'medium', array('itemprop'=>'image') ); } ?>
    </a>

<?php endforeach?>

我该如何解决？谢谢