2^31 packet counter bug?

Simon Andrew Boggis simon@dcs.qmw.ac.uk
Sun Dec 12 19:49:57 1999

> 2 billion packets and you're off the air...?
> The evil evidence:
> eth0      Link encap:Ethernet  HWaddr 00:90:27:50:A8:DE
>           inet addr:  Bcast:  Mask:
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:15 errors:288850 dropped:0 overruns:0 frame:0
>           TX packets:2147483647 errors:1 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:100
>           Interrupt:10 Base address:0xd000
> Check out the TX packets number!  That's 2^31-1.
> This is absolutely dreadful.  Is this 'feature' a
> property of the eepro100
> driver, or something in the kernel itself?
> Either way, it's a killer.  Gotta get to the bottom of it.
> Standard 2.2.12/2.2.13 kernels, with included eepro100 code.

Hmmm, I have a couple of eepro100-based linux routers - the one thats been up
the longest is working fine (167 days, kernel 2.2.9) but the counters are 
jammed - for example, `ifconfig eth0' gives:

eth0      Link encap:Ethernet  HWaddr 00:90:27:2A:55:48  
          inet addr:  Bcast:  Mask:
          IPX/Ethernet 802.2 addr:8A255800:0090272A5548
          RX packets:2147483647 errors:41 dropped:0 overruns:1 frame:0
          TX packets:2147483647 errors:13 dropped:0 overruns:715 carrier:0
          Interrupt:15 Base address:0xa000 

BUT /proc/net/dev reports something more believable:

hammer:/# cat net/dev      
Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
  eth0:2754574912 2177325200   41    0    1     0          0         0 2384782514 3474415357   13    0  715     0       0          0

Thats RX packets: 2177325200
and   TX packets: 3474415357

compared to     : 2147483647 from ifconfig eth0

So to me, it looks like neither the kernel (or the eepro100.c part thereof)
have a problem, rather that ifconfig isn't reporting the values correctly - 
which shouldn't have any impact on machine stability.

Could your network hang be a coincidence?


Simon A. Boggis 					Systems Programmer
Department of Computer Science, 
Queen Mary and Westfield College London, E1 4NS, UK. Telephone 0171 975 5234