18.04 rc-local.service exiting with error for read operation

[Raghavendra]

i have ubuntu 18.04.02 installed on my system

kernel version linux-image-4.15.0-45-generic

when i reboot rc-local.service does get execute but gives error as
read: read error: 0: Resource temporary unavailable

i run one shell script from rc.local where i perform read operation and take input from user.
the same script works well on system where i have installed ubuntu 16.04.05.

below is my rc-local.service file

[Unit]
Description=/etc/rc.local Compatibility
ConditionFileIsExecutable=/etc/rc.local
After=docker.service

[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=0
RemainAfterExit=yes

[Install]
 WantedBy=multi-user.target