Can confirm bug returns moving from kernel 4.15.0-32 to 4.15.0-33, tested on both 16.04 Server and 18.04 Server. Tested with program using pcap_inject (libpcap 1.7.4 (16.04) and libpcap 1.8.1 (18.04)), no issues seen with 4.15.0-32 (or 4.15.0-29), additional 14 bytes being transmitted with 4.15.0-33 and 4.15.0-34.
-- 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/1782544 Title: tcpreplay and veth device; extra transmit bytes on 4.4.0-130-generic kernel Status in linux package in Ubuntu: Confirmed Status in linux source package in Xenial: Confirmed Bug description: Issue found in a test harness for some code running on Ubuntu 16.04.4 LTS where we use a veth device to play in packets to the code under test. Essentially we see an extra 14 bytes being transmitted at the end of every packet that is just random garbage. Problem came in with the 4.4.0-130 kernel; if I revert to the 4.4.0-128 kernel the issue goes away. I have verified the issue on several different boxes running 16.04 The following steps reproduce the problem: 1) Veth setup sudo ip link add name nic1 type veth peer name nic2 sudo sysctl -q -w net.ipv6.conf.nic1.disable_ipv6=1 sudo sysctl -q -w net.ipv6.conf.nic2.disable_ipv6=1 sudo ip link set nic1 up sudo ip link set nic2 up 2) Configure tcpdump to collect packets on one interface: sudo tcpdump -i nic1 -w outPkts.pcap 3) Play in packets on the other (Any pcap will do): sudo tcpreplay -q -i nic2 inPkts.pcap When I check ifconfig I can see nic2/nic1 transmitting/receiving more bytes than expected. Opening the capture seen by tcpdump shows an extra 14 bytes received for every packet when compared to the input. tcpreplay version info: tcpreplay version: 3.4.4 (build 2450) (debug) Copyright 2000-2010 by Aaron Turner <aturner at synfin dot net> Cache file supported: 04 Not compiled with libdnet. Compiled against libpcap: 1.7.4 64 bit packet counters: enabled Verbose printing via tcpdump: enabled Packet editing: disabled Fragroute engine: disabled Injection method: PF_PACKET send() tcpdump version info tcpdump version 4.9.2 libpcap version 1.7.4 OpenSSL 1.0.2g 1 Mar 2016 ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: linux-image-4.4.0-130-generic 4.4.0-130.156 ProcVersionSignature: Ubuntu 4.4.0-130.156-generic 4.4.134 Uname: Linux 4.4.0-130-generic x86_64 NonfreeKernelModules: nvidia_uvm nvidia ApportVersion: 2.20.1-0ubuntu2.18 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: spw 3336 F.... pulseaudio /dev/snd/controlC0: spw 3336 F.... pulseaudio CurrentDesktop: Unity Date: Thu Jul 19 10:30:07 2018 HibernationDevice: RESUME=UUID=032369ab-18b8-41c3-a386-4ed08706f461 InstallationDate: Installed on 2016-11-03 (622 days ago) InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719) MachineType: Dell Inc. OptiPlex 7010 ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-130-generic root=UUID=7b20f97c-4edc-4af1-bdbb-72ccb26cfbec ro quiet splash intel_iommu=on RelatedPackageVersions: linux-restricted-modules-4.4.0-130-generic N/A linux-backports-modules-4.4.0-130-generic N/A linux-firmware 1.157.20 RfKill: SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/12/2013 dmi.bios.vendor: Dell Inc. dmi.bios.version: A15 dmi.board.name: 0KRC95 dmi.board.vendor: Dell Inc. dmi.board.version: A02 dmi.chassis.type: 6 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA15:bd08/12/2013:svnDellInc.:pnOptiPlex7010:pvr01:rvnDellInc.:rn0KRC95:rvrA02:cvnDellInc.:ct6:cvr: dmi.product.name: OptiPlex 7010 dmi.product.version: 01 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1782544/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
