Re: [lwip-users] ASSERT in tcp_input when moving PCB to front

[Kieran Mansley]

On Fri, 2007-05-18 at 08:49 -0700, David wrote:
> Hello guys, thanks for the hard work in lwip stack it
> a very nice
> piece of code that helps out a lot of people.
> 
> Now to the point, I am using lwip version 1.2.0 in my
> code and in some
> occasions i get hit with the first of the 2 ASSERTs
> you see below,
> before the pcb move. My question is the list is
> supposed to be a
> linear list that is NULL terminated, I was curious as
> to why these
> asserts were there, i guess someone has ran across my
> problem before
> and is protecting against it ? when and how could this
> self linking
> happen ?

I'm not sure who put them there or why, but the assertions look very
sensible to me.  As to how you could end up with a list containing a
loop like that, I'm not sure either.  A good candidate for internal
state corruption like this though is not sufficiently protecting the
stack against multiple threads accessing it at the same time.

Kieran