Oh, really? I think appreciate tag would be developer-emulating-work. Anyone can check that problem with ubuntu kernel 3.2 on every system, independently of hw configuration and bios version. More over, problem is fixed upstream.
-- 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/1177507 Title: per route mtu settings are broken in linux kernel 3.2 Status in “linux” package in Ubuntu: Confirmed Bug description: Hello, Looks like setting per route mtu (as described in [1]) is broken in linux kernel 3.2 (default kernel from ubuntu 12.04). I made script to illustrate this: root@germany7:~# cat route-mtu #!/bin/bash uname -a ip tuntap add dev test mode tun ifconfig test 10.1.1.1/16 mtu 1500 echo ============================================================= echo No per route mtu entry ping -c1 -Mdo -s2000 10.1.1.2 echo ============================================================= echo Per route MTU is set to 800 ip route add 10.1.1.2 dev test proto static src 10.1.1.1 mtu lock 800 ip route flush cache ping -c1 -Mdo -s2000 10.1.1.2 ip route del 10.1.1.2 dev test proto static src 10.1.1.1 mtu lock 800 echo ============================================================= echo Per route MTU is set to 600 ip route add 10.1.1.2 dev test proto static src 10.1.1.1 mtu lock 600 ip route flush cache ping -c1 -Mdo -s2000 10.1.1.2 ip route del 10.1.1.2 dev test proto static src 10.1.1.1 mtu lock 600 echo ============================================================= echo No per route mtu entry ip route flush cache ping -c1 -Mdo -s2000 10.1.1.2 ip tuntap del dev test mode tun With kernel 3.2 I get following output: Linux germany7 3.2.0-41-generic-pae #66-Ubuntu SMP Thu Apr 25 03:50:20 UTC 2013 i686 i686 i386 GNU/Linux ============================================================= No per route mtu entry PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 1500) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= Per route MTU is set to 800 PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 800) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= Per route MTU is set to 600 PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 800) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= No per route mtu entry PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 800) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors After once set to 800, MTU is always 800, even if you add different route and clean routing cache. It looks like that problem is fixed in ubuntu kernel 3.5. With it, everything works like expected: root@germany7:~# ./route-mtu Linux germany7 3.5.0-28-generic #48~precise1-Ubuntu SMP Wed Apr 24 21:43:05 UTC 2013 i686 i686 i386 GNU/Linux ============================================================= No per route mtu entry PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 1500) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= Per route MTU is set to 800 PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 800) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= Per route MTU is set to 600 PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 600) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors ============================================================= No per route mtu entry PING 10.1.1.2 (10.1.1.2) 2000(2028) bytes of data. From 10.1.1.1 icmp_seq=1 Frag needed and DF set (mtu = 1500) --- 10.1.1.2 ping statistics --- 0 packets transmitted, 0 received, +1 errors I also tested with kernels 2.6.35 (in lucid) and 3.8 (in precise), results are same to 3.5. Is there any chance to get fixes from 3.5/3.8 backported to the default precise kernel 3.2? 1. http://lartc.org/howto/lartc.cookbook.mtu-discovery.html --- AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24. ApportVersion: 2.0.1-0ubuntu17.2 Architecture: i386 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 0: Intel [HDA Intel], device 0: ALC268 Analog [ALC268 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: yura 2759 F.... pulseaudio Card0.Amixer.info: Card hw:0 'Intel'/'HDA Intel at 0xf4800000 irq 45' Mixer name : 'Intel Cantiga HDMI' Components : 'HDA:10ec0268,1025013c,00100101 HDA:14f12c06,10250093,00100000 HDA:80862802,80860101,00100000' Controls : 23 Simple ctrls : 10 CheckboxSubmission: 02f685f3381c5341bcbab31fdf0318b9 CheckboxSystem: 8278c9e6a57f68452a782d8924c0633a DistroRelease: Ubuntu 12.04 HibernationDevice: RESUME=UUID=2d28cf13-ba1f-4394-9958-51ed5ccb4dd3 MachineType: Acer Extensa 5630 MarkForUpload: True Package: linux (not installed) PccardctlIdent: Socket 0: no product info available PccardctlStatus: Socket 0: no card ProcFB: 0 inteldrmfb ProcKernelCmdLine: root=UUID=8f05626d-62de-43a5-87f9-1e51af186021 ro quiet splash resume=UUID=70081498-3f3e-4d20-8ccb-c31aebd900d6 ProcVersionSignature: Ubuntu 3.2.0-41.66-generic 3.2.42 RelatedPackageVersions: linux-restricted-modules-3.2.0-41-generic N/A linux-backports-modules-3.2.0-41-generic N/A linux-firmware 1.79.4 Tags: precise Uname: Linux 3.2.0-41-generic i686 UpgradeStatus: Upgraded to precise on 2013-05-09 (0 days ago) UserGroups: adm admin disk fuse pulse-access src sudo users wireshark WpaSupplicantLog: dmi.bios.date: 08/05/2008 dmi.bios.vendor: Phoenix Technologies LTD dmi.bios.version: V1.19 dmi.board.name: Homa dmi.board.vendor: Acer dmi.board.version: Rev dmi.chassis.type: 10 dmi.chassis.vendor: Acer dmi.chassis.version: N/A dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrV1.19:bd08/05/2008:svnAcer:pnExtensa5630:pvr0100:rvnAcer:rnHoma:rvrRev:cvnAcer:ct10:cvrN/A: dmi.product.name: Extensa 5630 dmi.product.version: 0100 dmi.sys.vendor: Acer To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1177507/+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
