Re: use-after-free in sock_wake_async

[Hannes Frederic Sowa <hannes@stressinduktion.org>]

On Thu, Nov 26, 2015, at 18:09, Eric Dumazet wrote:
> On Thu, 2015-11-26 at 18:03 +0100, Hannes Frederic Sowa wrote:
> 
> > My rationale was like this: we already have rcu to free the wq, so we
> > don't add any more callbacks as current code. sock_alloc is right now
> > 1136 bytes, which is huge, like 18 cachelines. I wouldn't think it does
> > matter a lot as we thrash anyway. tcp_sock is like 45 cachelines right
> > now, hui.
> 
> Again, these speculations are really killing me.
>
> Can you wait I send my patches ?

Eric, I wasn't targeting upstream. I just had this idea and wanted to
show you that it is possible. I didn't send an official patch and
wouldn't do that without proper performance analysis.

> They work just great, and there is no risk of perf regression with added
> RCU freeing of inodes :(

I agree. Your patch is certainly the best thing for net while this
complete rcuification should never ever hit net.

> It is Thanks Giving in the US, vacation time.

Enjoy the time! :)

Bye,
Hannes