Re: network packet corruption in v3.6.0-rc1 (and also in v3.5)

On Sat, 2012-08-18 at 16:40 +1000, Andrew Worsley wrote:

Some times I get a burst of errors and dropped tcp connections with
this warning. I had a similar issue with v3.5 (in fact v3.5 was
unusable for https connections which would give bad MAC code messages
at the application level)..

The issue seems better under v3.6-rc1 where as it was very bad under
v3.5. Let me know if there is something I can do to avoid this
problem. I am using the USB r8712u wireless NIC if that is relevant as
I haven't been able to get the native wireless working under the MAC
book yet (requires proprietary firmware extraction which I am not
familiar with)

Much obliged if there is anything I can do to avoid it as it is rather
annoying. Doesn't happen at all with my  Debian wheezy 3.2.0-2-amd64
kernel.

OK, this seems to be related to r8712u, still in staging tree.

At first glance, its using a buggy skb_clone(), or kind of a 'reuse skb'
trick I have no time to investigate.

I suspect that some memory area are overwritten by this driver, and this
was not noticed with older kernels. With new kernels, its triggering a
WARN_ON() in tcp stack.

Any chance you can try to reproduce the bug with another adapter ?