On 06/21/2018 10:05 AM, Juergen Gross wrote:
On 14/06/18 17:43, Javier Martinez Canillas wrote:
Hi Andrew,
On Wed, Jun 6, 2018 at 6:29 PM, Andrew Jeddeloh andrew.jeddeloh@redhat.com wrote:
Hi all,
The patch "xen-netfront: Fix race between device setup and open" seems to have introduced a regression preventing setting MTU's larger than 1500. We experienced this downstream with Container Linux and confirmed with Fedora 28 as well.
It's commit f599c64fdf7d9c108e8717fb04bc41c680120da4 in the linux-stable tree. https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/comm...
Downstream bugs: https://github.com/coreos/bugs/issues/2443 https://bugzilla.redhat.com/show_bug.cgi?id=1584216
We've confirmed that reverting that commit fixes the bug. It be reliably can be reproduced on AWS with t2.micro instances (and presumably other systems using the same driver). Both using systemd-networkd to set the mtu and manual ip link commands cause the link to repsond with "Invalid argument" when trying to set the MTU > 1500.
I'm not sure why that commit introduced the regression.
Please let me know if there's any more information that would be helpful.
- Andrew
I'm adding some relevant people to the CC list to bring more attention on this regression.
The get_maintainer.pl script is very useful to get some hints on who should be copied, i.e:
$ ./scripts/get_maintainer.pl -f drivers/net/xen-netfront.c
Ross, have you made any progress here? If not I'm thinking of reverting your patch as I think the current problem is more severe than the one your patch did address.
I've sent a patch today which I believe fixes the issue. Sorry for the slow response.
Regards,