Re: Rust kernel policy

James Bottomley
2025-02-19T14:14:19Z

On Wed, 2025-02-19 at 11:05 +0300, Dan Carpenter wrote:
> On Tue, Feb 18, 2025 at 08:08:18AM -0800, Christoph Hellwig wrote:
> > But that also shows how core maintainers are put off by trivial
> > things like checking for integer overflows or compiler enforced
> > synchronization (as in the clang thread sanitizer).
> > How are we're going to bridge the gap between a part of the kernel
> > that is not even accepting relatively easy rules for improving
> > safety vs another one that enforces even strong rules.
>
> Yeah.  It's an ironic thing...
>
>         unsigned long total = nr * size;
>
>         if (nr > ULONG_MAX / size)
>                 return -EINVAL;
>
> In an ideal world, people who write code like that should receive a
> permanent ban from promoting Rust.

I look at most of the bugfixes flowing through subsystems I watch and a
lot of them are in error legs. Usually around kfree cockups (either
forgetting or freeing to early). Could we possibly fix a lot of this
by adopting the _cleanup_ annotations[1]? I've been working in systemd
code recently and they seem to make great use of this for error leg
simplification.

Regards,

James

[1] https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-cleanup-variable-attribute