Re: [Xen-devel] [3.15-rc3] Bisected: xen-netback mangles packets between two guests on a bridge since merge of "TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy" series.
From: David Vrabel <hidden>
Date: 2014-05-07 08:17:00
On 06/05/14 19:07, Steven Haigh wrote:
On 07/05/14 03:37, Sander Eikelenboom wrote:quoted
Tuesday, May 6, 2014, 7:13:44 PM, you wrote:quoted
On 06/05/14 18:07, Steven Haigh wrote:quoted
On a related note, I'm seeing this on an Arch Linux DomU and kernel 3.14.2. Its running aria2c bit torrent client. The Dom0 is EL6 with Xen 4.2.4 / 3.14.2 kernel. I also lodged this on the Arch bug tracker: https://bugs.archlinux.org/task/40244 In a nutshell, I see: [ 7432.398096] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7434.270870] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7434.782199] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7435.184794] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7437.530677] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7437.973905] xen_netfront: xennet: skb rides the rocket: 19 slots [ 7438.383947] xen_netfront: xennet: skb rides the rocket: 19 slotsquoted
Can you also see packet corruption? You can find a testfile generator in Sander's mail, downloading from an Apache server with wget seems to be OK.The corruption shouldn't be there since he is running 3.14.2 which is fine. And note that the corruption with 3.15 only seems to occur in traffic between guests and not between dom0 and guest. The bit torrent traffic is probably inet <-> dom0 <-> guest, so shouldn't be affected, even with 3.15.Well, I'm trying to get a test together - although I don't have webdav anywhere... I was going to try it via FTP, however I'm hitting another MMU bug in Xen: https://bugs.archlinux.org/task/38596 This references: https://lkml.org/lkml/2014/1/23/596 It says that should be fixed in 3.15-rc3 (if I understand properly) - but I'm also hitting that on 3.14.2. Did these changes get ported back to the 3.14 tree?
This is fixed by 29c7787075 (mm: use paravirt friendly ops for NUMA hinting ptes) which is tagged for stable but hasn't yet been picked up for 3.14.y. You can also work around it by disabling CONFIG_NUMA_BALANCING which doesn't work with Xen PV guests anyway. David