Re: oops in tcp_xmit_retransmit_queue() w/ v2.6.32.15

Eric Dumazet
2010-07-15T12:05:35Z

Le jeudi 15 juillet 2010 à 13:58 +0200, Lennart Schulte a écrit :
> I'm testing new reordering algorithms in a virtual testbed, that is the
> nodes are emulated with xen and all the network parameters can be tuned
> with queues.
> With one of the algorithms I also got tracebacks which include
> tcp_xmit_retransmit_queue. It only happens with ACK loss. The kernel
> version however is 2.6.31.
> When I read this thread I tried the debug patch and got the following:
>
> [ 2754.413150] NULL head, pkts 0
> [ 2754.413156] Errors caught so far 1
>
> Hope that is of any help.

Not sure I understand.

Are you saying you reproduce same tcp_xmit_retransmit_queue() bug, with
a special tc qdisc/class droppping some ACK frames ?

Could it be some sched problem and incorrect return codes in case of
congestion ?