Re: [lwip-users] Underflow problem when reconnecting multiple times.

[Fabian Schneider]

Hello again,

I want to let you know that the issue has been solved.

It turns out the problem was not LWIP related but a problem with the operating system writing into memory it should not have.

I want to thank you all for your time and help.

Fabian

2016-07-28 10:35 GMT+02:00 Fabian Schneider <address@hidden>:

Hi everyone,

I have a question about a problem i've been having but cannot find the source of.

I've written a simple program that should connect to a server and transmit any data it gets from the OS to it. When the connection fails to establish it should simply close the connection and try again.

To do this i disable all callbacks and close the connection on either a close call from the OS or an tcp_err call.

After this i make a new pcb with tcp_new, rebind and try to connect again.

This works a few times but after failing to connect multiple times, i get the following error:

Assertion "detected memp underflow in pool 0" failed at line 307 in ../lwip/src/core/memp.c

I have tried closing and retrying the connection in many different ways, including not closing the connection and only doing so on a tcp_poll call. Yet i cannot seem to find the exact cause of the issue.

I also have an FTP and Web server running on this device that work without any issues.

I am using a single threaded custom OS with lwip 1.4.1 in raw mode. 

My question is. Is it clear to anyone what the problem could be,

Is there an issue with the way i close the connection or re-open it?

Thank you all very much,

Fabian