Arch Linux

captaincurrie

Member

From: /dev/random

Registered: 2013-11-01

Posts: 82

DHCP Client fails only when forking

Hello,

Really weird issue, Still not sure what its origin is but i thought i
should notify the community of it.

After a netctl restart, i got the following error message from dhcpcd.

	Mar 14 17:11:08 vessel dhcpcd[3237]: wlp2s0: IAID f8:a8:c0:7d
	Mar 14 17:11:09 vessel dhcpcd[3237]: wlp2s0: rebinding lease of 192.168.182.150
	Mar 14 17:11:09 vessel dhcpcd[3237]: wlp2s0: leased 192.168.182.150 for 600 seconds
	Mar 14 17:11:09 vessel dhcpcd[3237]: wlp2s0: adding route to 192.168.182.0/24
	Mar 14 17:11:09 vessel dhcpcd[3237]: wlp2s0: adding default route via 192.168.182.1
	Mar 14 17:11:09 vessel dhcpcd[3237]: forked to background, child pid 3277
	Mar 14 17:11:09 vessel wpa_actiond[3010]: Terminating wpa_actiond session for interface 'wlp2s0'
	Mar 14 17:11:10 vessel dhcpcd[3277]: arp_read: wlp2s0: Network is down
	Mar 14 17:11:10 vessel dhcpcd[3277]: dhcp_readpacket: wlp2s0: Network is down
	Mar 14 17:11:11 vessel dhcpcd[3277]: arp_announce1: Bad file descriptor

Panicking a bit (no wifi, no internet for me...) i rollbacked my root
filesystem (i use btrfs) to an earlier state a week before.  I rebooted
my system and i got the same issue. What?

Then i decided to try manually connecting to the network. dhcpcd silently failed a few times before i turned on
debug messages and the -B switch which forces it to stay in the foreground.
This worked.

It didn't click with me that this was the solution so i also tried dhclient and i got similar error messages

	Mar 14 20:15:00 vessel dhclient[13210]: DHCPDISCOVER on wlp2s0 to 255.255.255.255 port 67 interval 6
	Mar 14 20:15:00 vessel dhclient[13210]: DHCPOFFER of 192.168.1.186 from 192.168.1.1
	Mar 14 20:15:00 vessel dhclient[13210]: DHCPREQUEST for 192.168.1.186 on wlp2s0 to 255.255.255.255 port 67
	Mar 14 20:15:00 vessel dhclient[13210]: DHCPACK of 192.168.1.186 from 192.168.1.1
	Mar 14 20:15:00 vessel dhclient[13210]: Timeout too large reducing to: 2147483646 (TIME_MAX - 1)
	Mar 14 20:15:00 vessel dhclient[13210]: bound to 192.168.1.186 -- renewal in 2147483648 seconds.
	Mar 14 20:15:00 vessel wpa_actiond[12817]: Terminating wpa_actiond session for interface 'wlp2s0'
	Mar 14 20:15:01 vessel dhclient[13210]: receive_packet failed on wlp2s0: Network is down

Similar.

Anyways, eventually i realized that foregrounding the DHCP client
worked, so i edited /usr/lib/netctl/dhcp/dhcpcd to add the -B option and
everything seems to be working (haven't changed networks yet)

Anyways, very strange.

Notes

- This is unrealted to kernel
    - i tried with a 4.9 kernel and the latest 4.15 kernel
- netctl and its various components haven't been updated in over a month
  so i wouldn't point my finger there
- this might be some bizarre issue related to other things that have gone unnoticed.
    - that is, after doing a fresh reinstall this issue would go away