Re: Debug race condition

[Artur Grabowski <art@blahonga.org>]

"cmxu" <cmxu@rdsk.net> writes:

> Hello:
> 
>         i try to make openbsd work in polling mode (based on liug's work on
> freebsd), it works very well except ...
> 
>         When fxp0 under heavy traffic, if i run "ifconfig fxp0 up", system
> crashed!  it happened in fxp_add_rfabuf -> MCLGET,
> the mclfree->mcl_next suddenly changed to something like 0xa020xxxx, its a
> invalidat address. It seems there's some race condition.
> This is my first time try to hack openbsd kernel, maybe you guy can give me
> some advise on how to debug a race condition.

If I can look at your diffs I'll tell you within 10 minutes what your problem
was (I have a pretty good guess right now).

//art