Re: [PATCH v2 13/33] kmsan: Introduce memset_no_sanitize_memory()

[Alexander Potapenko]

On Tue, Nov 21, 2023 at 11:06 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> Add a wrapper for memset() that prevents unpoisoning.

We have __memset() already, won't it work for this case?
On the other hand, I am not sure you want to preserve the redzone in
its previous state (unless it's known to be poisoned).
You might consider explicitly unpoisoning the redzone instead.

...

> +__no_sanitize_memory
> +static inline void *memset_no_sanitize_memory(void *s, int c, size_t n)
> +{
> +       return memset(s, c, n);
> +}

I think depending on the compiler optimizations this might end up
being a call to normal memset, that would still change the shadow
bytes.