Session: Error while trying to free lock for ci_session

I'm on AWS ElasticBeanstalk. My install script is basically the same:

Code:

commands:
 01_redis_install:
   cwd: /home/ec2-user/phpredis-3.1.1
   test: '[ ! -f /etc/php.d/redis.ini ]'
   command: 'phpize && ./configure --enable-redis && make && make install && echo extension=redis.so > /etc/php.d/redis.ini'
 02_redis_cleanup:
   cwd: /home/ec2-user
   test: '[ -f /home/ec2-user/phpredis-3.1.1/README.markdown ]'
   command: 'sudo rm -rf phpredis-3.1.1'

Are you calling session_write_close on every AJAX call you make?