Re: Linux 4.14-rc6 bisected regression tun devices not working anymore in openvpn

[David Miller]

From: Cong Wang 
Date: Sat, 28 Oct 2017 10:37:27 -0700

> On Sat, Oct 28, 2017 at 7:57 AM, Sander Eikelenboom
>  wrote:
>> The offending commit is:
>> 0ad646c81b2182f7fa67ec0c8c825e0ee165696d
>> "tun: call dev_get_valid_name() before register_netdevice()"
>>
>> Reverting this commit fixes the issue for me, it's unfortunate that the 
>> commit it self seems to fix an other issue.
> 
> It should be fixed by:
> 
> commit 5c25f65fd1e42685f7ccd80e0621829c105785d9
> Author: Julien Gomes 
> Date:   Wed Oct 25 11:50:50 2017 -0700
> 
> tun: allow positive return values on dev_get_valid_name() call

I made sure to queue this up for -stable since the offending commit is queued up
there as well.

Re: Linux 4.14-rc6 bisected regression tun devices not working anymore in openvpn

[Cong Wang]

On Sat, Oct 28, 2017 at 7:57 AM, Sander Eikelenboom
 wrote:
> L.S.,
>
> While testing a linux 4.14-rc6 kernel i noticed OpenVPN didn't function 
> anymore.
> My openvpn config uses tun devices and is pretty standard.
> The openvpn version is current Debian stable: openvpn 2.4.0-6+deb9u2
>
> From the openvpn logging:
> Sat Oct 28 16:03:34 2017 us=175829 TUN/TAP device  opened
> Sat Oct 28 16:03:34 2017 us=183027 Note: Cannot set tx queue length on : 
> No such device (errno=19)
> Sat Oct 28 16:03:34 2017 us=183055 do_ifconfig, 
> tt->did_ifconfig_ipv6_setup=0
> Sat Oct 28 16:03:34 2017 us=183071 /sbin/ip link set dev  up mtu 1500
> Cannot find device ""
> Sat Oct 28 16:03:34 2017 us=200445 Linux ip link set failed: external 
> program exited with error status: 1
> Sat Oct 28 16:03:34 2017 us=200482 Exiting due to fatal error
> Sat Oct 28 16:38:17 2017 us=923381 TCP/UDP: Closing socket
> Sat Oct 28 16:38:17 2017 us=925986 Closing TUN/TAP interface
>
>
> The offending commit is:
> 0ad646c81b2182f7fa67ec0c8c825e0ee165696d
> "tun: call dev_get_valid_name() before register_netdevice()"
>
> Reverting this commit fixes the issue for me, it's unfortunate that the 
> commit it self seems to fix an other issue.

It should be fixed by:

commit 5c25f65fd1e42685f7ccd80e0621829c105785d9
Author: Julien Gomes 
Date:   Wed Oct 25 11:50:50 2017 -0700

tun: allow positive return values on dev_get_valid_name() call

If the name argument of dev_get_valid_name() contains "%d", it will try
to assign it a unit number in __dev__alloc_name() and return either the
unit number (>= 0) or an error code (< 0).
Considering positive values as error values prevent tun device creations
relying this mechanism, therefor we should only consider negative values
as errors here.

Signed-off-by: Julien Gomes 
Acked-by: Cong Wang 
Signed-off-by: David S. Miller 


Sorry for the trouble.

Thanks.

Linux 4.14-rc6 bisected regression tun devices not working anymore in openvpn

[Sander Eikelenboom]

L.S.,

While testing a linux 4.14-rc6 kernel i noticed OpenVPN didn't function 
anymore. 
My openvpn config uses tun devices and is pretty standard.
The openvpn version is current Debian stable: openvpn 2.4.0-6+deb9u2

>From the openvpn logging:
Sat Oct 28 16:03:34 2017 us=175829 TUN/TAP device  opened
Sat Oct 28 16:03:34 2017 us=183027 Note: Cannot set tx queue length on : No 
such device (errno=19)
Sat Oct 28 16:03:34 2017 us=183055 do_ifconfig, 
tt->did_ifconfig_ipv6_setup=0
Sat Oct 28 16:03:34 2017 us=183071 /sbin/ip link set dev  up mtu 1500
Cannot find device ""
Sat Oct 28 16:03:34 2017 us=200445 Linux ip link set failed: external 
program exited with error status: 1
Sat Oct 28 16:03:34 2017 us=200482 Exiting due to fatal error
Sat Oct 28 16:38:17 2017 us=923381 TCP/UDP: Closing socket
Sat Oct 28 16:38:17 2017 us=925986 Closing TUN/TAP interface


The offending commit is: 
0ad646c81b2182f7fa67ec0c8c825e0ee165696d
"tun: call dev_get_valid_name() before register_netdevice()" 

Reverting this commit fixes the issue for me, it's unfortunate that the commit 
it self seems to fix an other issue.

--
Sander