Find the Procs
After upgrading an important package in Linux -or other Unix variant- that provides a library used by many other processes. Instead of restarting the server for the new lib to take effect, the procs can be restarted -or HUPed- individually.
Before we begin, lsof needs to be installed.
# RHEL / CentOS
~$ yum install lsof
# Debian / Ubuntu
~$ apt-get install lsof
In the following example, we list what processes are using the libcrypto library in Raspbian.
~$ lsof /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sshd 551 root mem REG 179,2 1418532 10074 /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
ntpd 2321 ntp mem REG 179,2 1418532 10074 /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
sshd 6643 root mem REG 179,2 1418532 10074 /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
sshd 6649 meow mem REG 179,2 1418532 10074 /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
openvpn 30044 nobody mem REG 179,2 1418532 10074 /usr/lib/arm-linux-gnueabihf/libcrypto.so.1.0.0
Next, the affected processes can be restarted:
~$ service [SERVICENAME] restart
~$ systemctl restart [SERVICENAME]
~$ kill -HUP 31337
root