Re: [PATCH] dmaengine: ioatdma: use !kstrtoint(), not sscanf()!=-1

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The sysfs store function silently ignores parsing errors and incorrectly returns success (`count`) when given invalid input.
--

commit fe01246cf60369a73aac5e63b92278079b4417aa
Author: Alexander A. Klimov <grandmaster@al2klimov.de>
dmaengine: ioatdma: use !kstrtoint(), not sscanf()!=-1

The commit replaces the use of sscanf() with kstrtoint() in the sysfs store
function to parse user input. It also addresses a checkpatch.pl warning
regarding the formatting string.

> diff --git a/drivers/dma/ioat/sysfs.c b/drivers/dma/ioat/sysfs.c
> index e796ddb5383f8..f59df569956ae 100644
> --- a/drivers/dma/ioat/sysfs.c
> +++ b/drivers/dma/ioat/sysfs.c
> @@ -144,7 +144,7 @@ size_t count)
>  	int intr_coalesce = 0;
>  	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
>  
> -	if (sscanf(page, "%du", &intr_coalesce) != -1) {
> +	if (!kstrtoint(page, 10, &intr_coalesce)) {
>  		if ((intr_coalesce < 0) ||
>  		    (intr_coalesce > IOAT_INTRDELAY_MASK))
>  			return -EINVAL;

[Severity: Medium]
If kstrtoint() fails to parse the input and returns a negative error code,
the condition evaluates to false and the function skips the block.

Looking at the remainder of intr_coalesce_store(), execution then jumps
directly to the end of the function:

	if (!kstrtoint(page, 10, &intr_coalesce)) {
		...
		ioat_chan->intr_coalesce = intr_coalesce;
	}

	return count;

Does this silently ignore parsing errors and incorrectly indicate to userspace
that the write was successful when given invalid input?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260526061321.6123-3-grandmaster@al2klimov.de?part=1