Re: [PATCH v2 08/10] drivers/auxdisplay: add a KFuzzTest for parse_xy()

[Andy Shevchenko]

On Fri, Sep 19, 2025 at 5:58 PM Ethan Graham <ethan.w.s.graham@xxxxxxxxx> wrote:
>
> From: Ethan Graham <ethangraham@xxxxxxxxxx>
>
> Add a KFuzzTest fuzzer for the parse_xy() function, located in a new
> file under /drivers/auxdisplay/tests.
>
> To validate the correctness and effectiveness of this KFuzzTest target,
> a bug was injected into parse_xy() like so:
>
> drivers/auxdisplay/charlcd.c:179
> - s = p;
> + s = p + 1;
>
> Although a simple off-by-one bug, it requires a specific input sequence
> in order to trigger it, thus demonstrating the power of pairing
> KFuzzTest with a coverage-guided fuzzer like syzkaller.

...

> --- a/drivers/auxdisplay/charlcd.c
> +++ b/drivers/auxdisplay/charlcd.c
> @@ -682,3 +682,11 @@ EXPORT_SYMBOL_GPL(charlcd_unregister);
>
>  MODULE_DESCRIPTION("Character LCD core support");
>  MODULE_LICENSE("GPL");
> +
> +/*
> + * When CONFIG_KFUZZTEST is enabled, we include this _kfuzz.c file to ensure
> + * that KFuzzTest targets are built.
> + */
> +#ifdef CONFIG_KFUZZTEST
> +#include "tests/charlcd_kfuzz.c"
> +#endif /* CONFIG_KFUZZTEST */

No, NAK. We don't want to see these in each and every module. Please,
make sure that nothing, except maybe Kconfig, is modified in this
folder (yet, you may add a _separate_ test module, as you already have
done in this patch).

-- 
With Best Regards,
Andy Shevchenko