Bug#709616: floods the network with pause packets

[Stéphane Glondu <glondu@debian.org>]

Le 24/05/2013 18:07, Ben Hutchings a écrit :
>> With Linux 3.8, my computer starts (after some time) flooding its
>> network interface with pause packets, effectively freezing it and
>> other network-dependent computers connected to the same switch.
> 
> Switches should normally be configured to generate but not respond
> to pause frames.  I don't know how unmanaged switches are typically
> configured.  What do ethtool (no options and 'ethtool -a' report for
> this device?

The other frozen computers are connected via an unmanaged switch.

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 2
        Transceiver: internal
        Auto-negotiation: on
        MDI-X: off
        Supports Wake-on: pumbg
        Wake-on: g
        Current message level: 0x00000001 (1)
                               drv
        Link detected: yes
# ethtool -a eth0
Pause parameters for eth0:
Autonegotiate:  on
RX:             on
TX:             on

>> When I connect directly my laptop to the computer, and run tcpdump on
>> the laptop, I see:
>> [...]
> There seems to be a bug in your laptop's network driver, because pause
> frames should not be passed to the kernel.  (Usually they are
> discarded by the MAC.)

Even in promiscuous mode?

> [...]
>> 00:19.0 Ethernet controller [0200]: Intel Corporation 82579LM Gigabit Network Connection [8086:1502] (rev 04)
>> 	Subsystem: Hewlett-Packard Company Device [103c:1494]
>> 	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx+
>> 	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
>> 	Latency: 0
>> 	Interrupt: pin A routed to IRQ 46
>> 	Region 0: Memory at fe400000 (32-bit, non-prefetchable) [size=128K]
>> 	Region 1: Memory at fe428000 (32-bit, non-prefetchable) [size=4K]
>> 	Region 2: I/O ports at f080 [size=32]
>> 	Capabilities: <access denied>
>> 	Kernel driver in use: e1000e
> [...]
>  
> I assume this is the device that's spewing pause frames?

You assume right.


Cheers,

-- 
Stéphane