Re: [lwip-users] memory leak ?

[Sylvain Rochet]

Hello Jan,

On Thu, Jun 04, 2015 at 02:34:39PM +0200, Jan Menzel wrote:
> Hi Noam!
>       From earlier discussion on this list, I learned that for this purpose
> one may schedule a callback into the LWIPs internal task using
> tcpip_callback() or tcpip_callback_with_blocking(). Both queue your
> function and its arguments for execution from within the main Lwip task
> context. I'm not sure if this is applicable here, but if so, I would
> favour the callback solution as yours might introduce dead locks in case
> tcp_sndbuf() blocks. This type of errors are comparably difficult to
> find and likely to happen if eg. an other task is used to free buffers
> after transmission completed.

You are right.

For future readers which might looks at this thread in the hope of 
getting a clue, please don't get fooled !, what Noam is doing is 
completely wrong. Adding a critical section and playing with thread 
priority this way is either dangerous or just stupid. (And don't tell me 
that it is working, I don't care if it -appears- to work).

OS users HAVE TO use the Netconn or Socket API if they want to call lwIP 
functions from others threads, period. RAW API is ***NOT*** thread-safe.

I repeat, RAW API is ***NOT*** thread-safe.

Sylvain

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