LNMP Upgrade PHP 502 Bad Gateway Error

LNMP upgrade php5.4.28 or later version error 502 bad Gateway
Encounter a very strange problem, with LNMP./upgrade_php.sh upgrade php5.4.27 normal.
But upgrade to php5.4.28 error, Access p.php hint: Nginx 502 bad Gateway. Try again in the morning, upgrade to 5.5.12 access p.php is also the same hint: Nginx 502 Bad Gateway
The prompts for the upgrade are all successful, PHP-FPM also prompts to start successfully.

But access to the p.php page on the tip: 502, is not PHP 5.4.28 version of the installation configuration changes.

Environment:
CentOS 6.5 x86_64
Nginx 1.60
MySQL 5.5

Workaround:
Add listen underneath the/usr/local/php/etc/php-fpm.conf.
Listen.backlog =-1
Listen.allowed_clients = 127.0.0.1
Listen.owner = www
Listen.group = www
Listen.mode = 0666
Restart PHP-FPM

Test problem resolution.