Re: exit_mmap BUG_ON in 2.6.23 (and Add qdisc __NET_XMIT_STOLEN)

[Eric Dumazet <eric.dumazet@gmail.com>]

On Fri, 2012-05-25 at 22:27 -0700, Sam Portolla wrote:

> Yes, thanks I had looked at the kernel  code and know how transmit
> timeouts come to be in normal cases. The driver specifies a timeout
> period to the network layer, along with a callback function to call in
> case of Tx timeout so the driver can do error handling which is
> typically to reset the driver (and this happened in the case of the
> BNX2 linux driver our system uses as well). Above I had asked some
> specific questions with regards to whether a known bug w/ qdisc could
> stop the Tx Q's to the device and thereby cause traffic timeouts. Also
> it seems from the email thread on the patch I had mentioned above that
> the qdisc issue can cause memory corruption, which could then tie it
> in with the BUG_ON in exit_mmap() which Hugh had previously commented
> on. I am hoping the engineers who fixed the QDISC issue can comment on
> the former and Hugh can comment on the BUG_ON again. Regards. 


The commit you mention is about a very unusual use of qdiscs.
I really doubt it is your problem.
Most advanced tc users probably wont stick with 2.6.23 kernels.

Please post :

tc -s -d qdisc

And for all your network devices : 

for DEV in eth0 eth1 eth2
do
tc -s -d class show dev $DEV
done