[lwip-users] LWIP 1.1.0 stability issue

[Kjell-Erik Klevan]

Hi!

This is my first email to this forum so be nice to me :-)

We have an IP input board equipped with a TI DM642 DSP running the LWIP
version 1.1.0 stack. More, the board contains two Intel gigabit Ethernet
controllers. One that communicates with the outside world and one that only
communicates internally with other boards in the unit (typically data
processor boards).

We have some stability issues with the LWIP stack and are easily provoked
during FTP test (upload and download of files). When it occurs, the board
does not respond even to ping. However, it still transmits and receives ARP
messages. 

During test, we encountered the following printouts:
Closing data socket 23
mem_malloc: could not allocate 1096 bytes
tcp_enqueue : could not allocate memory for pbuf copy size 1024

Note that this is only one way for us to provoke it. It also happens
sometimes with other TCP applications (like Telnet) but without any
warnings.

Looking more through the code I started wondering about the TCP part of the
stack. tcp_active_pcbs variable that keeps track of the list of active TCP
connections is not protected by any semaphore. The timer function
"tcp_slowtmr" and the thread "tcpip_thread" are both using this list. To me,
it seems that this list can be corrupted if no semaphore protection is
added. OR is it something that I am missing here?

Thanks for any help or guidelines you can give.

Regards,
Kjell-Erik