Inspection of the core dump and some testing proves the Segmentation fault error is caused by denied permission to read /proc/self/cmdline. Moving the executable anywhere else the problem would simply disappear.
Further inspection pointed the cause to be apparmor denied the open file call, thus, the obvious workaround is remove /sbin/dhclient's apparmor from enforcing mode: sudo apt install apparmor-utils sudo aa-complain /sbin/dhclient This would allow the dhclient to run without error. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to isc-dhcp in Ubuntu. https://bugs.launchpad.net/bugs/1696499 Title: dhclient segfaults on ubuntu 17.04 Status in isc-dhcp package in Ubuntu: Confirmed Bug description: After upgrading, network-manager stopped running DHCP, after trying to run dhclient myself I found out it segfaults. Attached is its strace output. I can connect to the internet by stopping network-manager and using ifconfig + route + /etc/resolv.conf. Output: guy@golem4:~$ dhclient Segmentation fault (core dumped) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/1696499/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
