Re: [lwip-users] TCP Crash after repeated calls [Raw]

[Kieran Mansley]

On Wed, 2009-07-22 at 21:22 -0700, Chris_S wrote:
> This is all I get on the 2nd refresh attempt.  There is no lwIP ACK to the
> SYN, yet CPU is not crashed,
> and PINGs still work.  But no more TCP.
> 
> 3381 149409.829866 192.168.2.10 192.168.2.1 TCP unisql > http [SYN] Seq=0
> Win=25200 Len=0 MSS=1460
> 3382 149412.828834 192.168.2.10 192.168.2.1 TCP unisql > http [SYN] Seq=0
> Win=25200 Len=0 MSS=1460

Ignoring the crash for the time being as you think that might be related
to the debug output itself, the messages shown above show that lwIP is
still receiving packets from the network, and recognising them as new
connection requests.  However it doesn't want to send a packet in
response, which is rather odd.  The usual reason for something like this
is that the stack has run out of packet buffers due to a leak, but in
your case the stats show that everything is fine in that regard.

Can you describe the application you're using on top of lwIP in more
detail, particularly with regard to how its threads (if any) are
structured and how they access lwIP?

Thanks

Kieran