Arch Linux

-thc

Member

Registered: 2017-03-15

Posts: 502

[SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Hi there,

After upgrading the Arch kernel to 4.10 my VPN connections started behaving erratic.

- Immediately after booting Arch the VPNs will work
- After closing VPN connections restarting them will work or not
- Restart success is completely random (yes, no, no, yes, yes, no, no, no, yes....)
- The first TAP device (tap0) seems highly affected - the others (tap1, tap2...) not so much, but sometimes too

The system log shows these errors:

  NetworkManager[387]: <error> [1489564063.9337] platform-linux: do-add-ip4-address[3: 192.168.X.X/24]: failure 19 (No such device)

and a lot of

  nm-openvpn[1225]: write to TUN/TAP : Input/output error (code=5)

"ifconfig tap0" shows tap0 is existing but not configured. "route" shows the routes for tap0 are missing.

Downgrading the Kernel to 4.9.11 immediately solves this problem.

Last edited by -thc (2017-03-24 17:05:00)

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Your problem seems to be similar to this https://bbs.archlinux.org/viewtopic.php?id=224056

Have you tried to trigger the problem by using openvpn directly?

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R00KIE
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-thc

Member

Registered: 2017-03-15

Posts: 502

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Calling OpenVPN manually will always lead to a working connection. Unfortunately in my line of work I have to handle 7 primary and 4 secondary VPNs. Activating several of them at a time and switching between primary ones and secondary ones is part of my everyday work. Handling that without a decent manager app is cumbersome.

I tried downgrading networkmanager to 1.6.2-1 and networkmanager-openvpn to 1.2.8-1 - the errors stay the same. Only downgrading the kernel mitigates this problem.

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Instead of downgrading the kernel you might want to consider using the LTS kernel, as that is maintained and receives bug and security fixes.

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R00KIE
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-thc

Member

Registered: 2017-03-15

Posts: 502

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Thanks for hinting the LTS kernel. I did that & it's the best working solution. I will check future non-LTS kernels for this glitch.

-thc

Member

Registered: 2017-03-15

Posts: 502

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Update 4.10.3: Problem persists.

-thc

Member

Registered: 2017-03-15

Posts: 502

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Update 4.10.4: Problem persists.

-thc

Member

Registered: 2017-03-15

Posts: 502

Re: [SOLVED] Kernel 4.10 shows erratic VPN behavior (tapX setup)

Update 4.10.5: Problem resolved.