Re: [PATCH 16/24] link_path_walk: kill the recursion

Linus Torvalds
2015-04-20T21:41:34Z

On Mon, Apr 20, 2015 at 2:32 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> A kilobyte would suffice for 32 levels. _IF_ we go for "lift the restrictions
> on nesting completely", sure, we want to switch to (on-demand) dynamic
> allocation.

And no, we will *never* lift the recursion limit. Not for 1kB, not for
1MB. Never.

Because it's a latency and DoS issue too. We need to react well to
true loops, but also to "very deep" non-loops. It's not about memory
use, it's about users triggering unreasonable CPU resources.

Linus