Looking at the delta I found this change (referencing the upstream commit which was received via upstream stable):
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbcf24d153884439dad30484a0e3f02350692e4c This sounds like LRO should not have been configurable and they (upstram) fixed that now. And they claim any problem are not theirs... (at least I read it that way). Commit a02e8964eaf92 ("virtio-net: ethtool configurable LRO") maps LRO to virtio guest offloading features and allows the administrator to enable and disable those features via ethtool. This leads to several issues: - For a device that doesn't support control guest offloads, the "LRO" can't be disabled triggering WARN in dev_disable_lro() when turning off LRO or when enabling forwarding bridging etc. - For a device that supports control guest offloads, the guest offloads are disabled in cases of bridging, forwarding etc slowing down the traffic. Fix this by using NETIF_F_GRO_HW instead. Though the spec does not guarantee packets to be re-segmented as the original ones, we can add that to the spec, possibly with a flag for devices to differentiate between GRO and LRO. Further, we never advertised LRO historically before a02e8964eaf92 ("virtio-net: ethtool configurable LRO") and so bridged/forwarded configs effectively always relied on virtio receive offloads behaving like GRO - thus even if this breaks any configs it is at least not a regression. Fixes: a02e8964eaf92 ("virtio-net: ethtool configurable LRO") -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1946185 Title: large-receive-offload no more tunable in 5.4.0-89-generic Status in linux package in Ubuntu: Won't Fix Bug description: While debugging a bug 1945868 I found something that I think is a separate issue to that original report, hence this new bug. I found the virtio-net behavior changing in an unexpected way in 5.4.0-89-generic that is currently in Focal-proposed. 1. 5.4.0-86-generic $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off $ sudo ethtool --features enp1s0 lro on $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: on $ sudo ethtool --features enp1s0 lro off $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off 2. 5.4.0-88-generic $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off $ sudo ethtool --features enp1s0 lro on $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: on $ sudo ethtool --features enp1s0 lro off $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off 3. 5.4.0-89-generic $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off [fixed] $ sudo ethtool --features enp1s0 lro on Cannot change large-receive-offload Could not change any device features $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off [fixed] $ sudo ethtool --features enp1s0 lro off Cannot change large-receive-offload $ sudo ethtool --show-features enp1s0 | grep large large-receive-offload: off [fixed I've installed/uninstalled the guest kernel twice but the above behavior remained consistent and seemed to be only influenced by the new kernel. The used guest config is the default that falls out of uvt-kvm, that means in regard to this bug: <os> <type arch='x86_64' machine='pc-q35-focal'>hvm</type> </os> ... <interface type='network'> <mac address='52:54:00:b2:c2:2a'/> <source network='default'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </interface> Virt-Stack is qemu 1:4.2-3ubuntu6.17 and libvirt 6.0.0-0ubuntu8.14 from current Focal-updates. --- ProblemType: Bug AlsaDevices: total 0 crw-rw---- 1 root audio 116, 1 Oct 6 06:47 seq crw-rw---- 1 root audio 116, 33 Oct 6 06:47 timer AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.20.11-0ubuntu27.20 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: N/A CasperMD5CheckResult: skip DistroRelease: Ubuntu 20.04 IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig' Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Lsusb-t: /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M MachineType: QEMU Standard PC (Q35 + ICH9, 2009) Package: linux (not installed) PciMultimedia: ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-89-generic root=UUID=5697bbf9-a186-49b9-98bc-2a94313535b4 ro console=tty1 console=ttyS0 ProcVersionSignature: Ubuntu 5.4.0-89.100-generic 5.4.143 RelatedPackageVersions: linux-restricted-modules-5.4.0-89-generic N/A linux-backports-modules-5.4.0-89-generic N/A linux-firmware N/A RfKill: Error: [Errno 2] No such file or directory: 'rfkill' Tags: focal uec-images Uname: Linux 5.4.0-89-generic x86_64 UnreportableReason: This report is about a package that is not installed. UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: N/A _MarkForUpload: False dmi.bios.date: 04/01/2014 dmi.bios.vendor: SeaBIOS dmi.bios.version: 1.13.0-1ubuntu1.1 dmi.chassis.type: 1 dmi.chassis.vendor: QEMU dmi.chassis.version: pc-q35-focal dmi.modalias: dmi:bvnSeaBIOS:bvr1.13.0-1ubuntu1.1:bd04/01/2014:svnQEMU:pnStandardPC(Q35+ICH9,2009):pvrpc-q35-focal:cvnQEMU:ct1:cvrpc-q35-focal: dmi.product.name: Standard PC (Q35 + ICH9, 2009) dmi.product.version: pc-q35-focal dmi.sys.vendor: QEMU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1946185/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
