Re: [TECH TOPIC] Rust

[Dan Carpenter <dan.carpenter@oracle.com>]

On Sun, Jun 19, 2022 at 04:49:18PM +0300, Laurent Pinchart wrote:
> Writing rust code that compiles (without wrapping everything in unsafe)
> requires understanding of life time management of objects. This is also
> required to write safe C code, but as can be seen through the kernel
> it's more often that not completely ignored, especially in drivers (just
> look at how many drivers that expose a chardev to userspace are happy
> using devm_kzalloc() to allocate their private data structure that is
> accessible through userspace calls). It may be caused by a combination
> of both the compiler an the kernel allowing bad practices (the fact that
> devm_kzalloc() exists without a huge flashing red warning around it
> shows that we either don't understand the problem or don't care),

The answer is that we don't understand the problem.  I've been vaguely
aware that there is a problem related to this but I've never been clear
enough to the point where I could actually tell if code is buggy.

It sounds like something which could probably be detected with static
analysis.  Most of the static analysis devs hang out on kernel-janitors
so if you see a bug and you think it might happen more than once then
send an email to kernel-janitors@vger.kernel.org.

Sometimes if we look at a patch then maybe we can identify several
heuristics to spot the bug.

regards,
dan carpenter