[lwip-users] lwip and MPU (FreeRTOS-MPU)

[jblackarty]

Hi all,

I've ported lwip to FreeRTOS-MPU (ARM Cortex-M3, GCC) and suddenly
found that lwip design violates FreeRTOS memory access
restrictions. The problem is that lwip tcpip thread accesses local
variable allocated on stack of application thread which uses Netconn
API. FreeRTOS-MPU protects thread stacks because stack corruption
(made by other threads) can corrupt freertos kernel data and thus
cause crash of whole system
LwIP is most unreliable (because most complex) component in my
system. Therefore, it's first candidate to have most rectricted access
rights in my system. Ironically, it happened that I'm forced to give
it access to application thread stacks and thus make it the only
component which may cause whole system crash ! And seems like it does
it already in my tests, but I'm not sure so far because I didn't found
that it's lwip who does it (it's only a week passed since I started
debbugging which driving me crazy).
I have absolutely no idea how to solve it keeping lwip code
unmodified. What do you think about it ?

Regards,
Artem Pisarenko