[en0:rtl8168_rx_interrupt] Rx packet size() > mtu()+14!

[thefsb]

LAN down after boot today.

BIOS Smart LAN shows link healthy. OS X reports the link up, with green light and all appearing normal except packets don't flow. I tried a known good cable which didn't help.

I installed the debug version of lnx2max via RealtekRTL81xx-0_0_90.pkg. Now the debug messages all look just fine except the one in the subject line. When in System Preferences/Network I enable the ethernet, the following log messages are seen:

10/20/11 9:45:22.733 AM configd: SCNC: stop, type PPPSerial
10/20/11 9:45:22.735 AM configd: network configuration changed.
10/20/11 9:45:23.000 AM kernel: [en0:enable()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:setActivationLevel((level=2))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:increaseActivationLevel((level=1))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:RTL81xxOpenAdapter()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_hw_start()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_nic_reset()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_nic_reset] returns
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_dsm((dev_state=1))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_dsm] returns
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_hw_start] returns WOL=1
10/20/11 9:45:23.000 AM kernel: [en0:setWakeOnMagicPacket((active=0))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_set_wol((wol->wolopts=0x0000))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:setWakeOnMagicPacket] returns kIOReturnSuccess
10/20/11 9:45:23.000 AM kernel: [en0:RTL81xxOpenAdapter] returns rv=true
10/20/11 9:45:23.000 AM kernel: [en0:increaseActivationLevel] Selected medium index 7
10/20/11 9:45:23.000 AM kernel: [en0:selectMedium()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:selectMedium] selectMedium, index=7
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_set_speed_xmii((autoneg=0x01, speed=0x0003, duplex=0x02))] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_phy_power_up()] Enter
10/20/11 9:45:23.000 AM kernel: [en0:rtl8168_phy_power_up] returns
10/20/11 9:45:25.000 AM kernel: 68_rx_interrupt] Rx packet size() > mtu()+14!
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx packet size() > mtu()+14!
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx packet size() > mtu()+14!
... this message repeats 160 times in total ...
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx packet size() > mtu()+14!
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx packet size() > mtu()+14!
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx overflow recovery complete
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx overflow detected! Starting recovery
10/20/11 9:45:25.000 AM kernel: [en0:rtl8168_rx_interrupt] Rx overflow recovery complete
10/20/11 9:46:27.249 AM configd: network configuration changed.

 

[thefsb]

Deleting lnx2mac and installing Realtek didn't get connectivity back.

After much time wasting, I resolved the problem by deleting:
/Library/Preferences/SystemConfiguration/

• preferences.plist [/*:m:1vkwujxj]
• NetworkInterfaces.plist [/*:m:1vkwujxj]
• com.apple.network.identification.plist [/*:m:1vkwujxj]
• com.apple.network.eapolclient.configuration.plist[/*:m:1vkwujxj]

So it wasn't a driver issue, it was an OS X config issue.

How did this happen?

 

[Lnx2Mac]

You probably modified MTU (configured jumbo packets, which are still unsupported)

 

[thefsb]

You probably modified MTU (configured jumbo packets, which are still unsupported)

Do you have any idea how that might have happened?

 

[thefsb]

This problem keeps recurring. I don't know what causes it.

It happened again today and I was not able to clear it by resetting or deleting configurations. I was only able to get networking back up by deleting the lnx2mac kext and reinstalling the Realtek driver.

mtu on the interface was definetly set to 1500. I even tried it on smaller values which made no difference.

I'd be glad to try stuff out for debugging purposes if anyone could suggest some tests...

 

[thefsb]

This problem keeps recurring.

Sometimes switching the interface off and on in Network Preferences clears it. Sometimes deleting files in /L/P/SystemConfiguration and rebooting clears it. And sometimes it takes several reboots.

Never did I adjust interface MTU. That config is set to auto and it always shows 1500.