Re: [PATCH v3 3/3] nvmem: mtk-efuse: add mt6572 support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Flawed string comparison logic in `mtk_efuse_fixup_dt_cell_info` allows unintentional prefix matching.
--

commit a7b90ac028ac0c3f0279ff49927a48455c13bc74
Author: Roman Vivchar <rva333@protonmail.com>

nvmem: mtk-efuse: add mt6572 support
    
This commit adds a platform data struct for the efuse controller to support
the MediaTek MT6572 SoC, configuring read alignment and post-processing
behavior.

> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index 178b9d85f813e..99d061eef6e33 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -132,6 +132,11 @@ static int mtk_efuse_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static const struct mtk_efuse_pdata mtk_mt6572_efuse_pdata = {
> +	.uses_post_processing = false,

[Severity: High]
This is a pre-existing issue, but while reviewing the post-processing logic
controlled by this flag, I noticed a potential flaw in how cell names are
matched.

In mtk_efuse_fixup_dt_cell_info(), the string comparison allows shorter strings
to falsely match as a prefix:

drivers/nvmem/mtk-efuse.c:mtk_efuse_fixup_dt_cell_info() {
    ...
	if (cell->nbits <= 3 &&
	    strncmp(cell->name, "gpu-speedbin", min(sz, strlen("gpu-speedbin"))) == 0)
		cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
    ...
}

Because it uses min(sz, strlen("gpu-speedbin")), wouldn't this incorrectly
apply GPU speedbin post-processing to any NVMEM cell whose name is merely a
prefix of "gpu-speedbin" (e.g., "gpu" or "gp") as long as it has nbits <= 3?

Could this lead to unintended data corruption by incorrectly modifying the
hardware read value for those unrelated NVMEM cells?

> +	.needs_aligned_read = true,
> +};
> +
>  static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
>  	.uses_post_processing = true,
>  	.needs_aligned_read = false,

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260909-6572-nvmem-v3-0-c0c441656431@protonmail.com?part=3