wordpress 版本： 5.3.2
环境：
跑在阿里云 ECS (centos8.0）+ RDS 上，使用Apache2.4、Mysql8.0、PHP7.2

进入Wordpress，点击安装时，报错如下：

Fatal error: Uncaught Error: Call to undefined function json_decode() in /var/www/wordpress/wp-includes/class-wp-block-parser.php:232 Stack trace: 
#0 /var/www/wordpress/wp-includes/blocks.php(521): WP_Block_Parser->parse('Twenty Twenty') 
#1 /var/www/wordpress/wp-includes/blocks.php(274): parse_blocks('Twenty Twenty') 
#2 /var/www/wordpress/wp-includes/formatting.php(4924): filter_block_content('Twenty Twenty', Array, Array) 
#3 /var/www/wordpress/wp-includes/class-wp-hook.php(288): wp_pre_kses_block_attributes('Twenty Twenty', Array, Array) 
#4 /var/www/wordpress/wp-includes/plugin.php(206): WP_Hook->apply_filters('Twenty Twenty', Array) 
#5 /var/www/wordpress/wp-includes/kses.php(914): apply_filters('pre_kses', 'Twenty Twenty', Array, Array) 
#6 /var/www/wordpress/wp-includes/kses.php(737): wp_kses_hook('Twenty Twenty', Array, Array) 
#7 /var/www/wordpress/wp-includes/class-wp-theme.php(827): wp_kses('Twenty Twenty', Array) 
#8 /var/www/wordpress/wp-includes/class-wp-theme.php(762): WP_Theme->sanitize_header('Name', 'Twenty Twe in /var/www/wordpress/wp-includes/class-wp-block-parser.php on line 232

查了好久，终于确定是php-json插件未安装。使用yum 命令安装，重启httpd、php-fpm后解决，命令如下：

yum install php-json
systemctl restart httpd
systemctl restart php-fpm