Re: [PATCH v3 10/11] nvdimm: ndtest: Return the string length from flags_show()

[Alison Schofield]

On Wed, Sep 30, 2026 at 04:52:38PM -0700, Kees Cook wrote:
> flags_show() build their output with a seq_buf and return seq_buf_used(),
> which may include the trailing NUL byte when the seq_buf has
> overflowed. Use seq_buf_strlen() instead.
> 
> The flag names are far shorter than the PAGE_SIZE buffer sysfs
> provides, so this cannot overflow today.
> 
> Build tested ARCH=x86_64 with GCC 16.2.0, built out of tree with
> make M=tools/testing/nvdimm:
> tools/testing/nvdimm/test/ndtest.o
> 
> Assisted-by: LLM
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> Signed-off-by: Kees Cook <kees@xxxxxxxxxx>


Hi Kees,

Should I include this one in a 7.4 PR for nvdimm or is someone else
merging the entire series?

-- Alison



> ---
>  tools/testing/nvdimm/test/ndtest.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/nvdimm/test/ndtest.c b/tools/testing/nvdimm/test/ndtest.c
> index 2051ad5d4882..f097f2992966 100644
> --- a/tools/testing/nvdimm/test/ndtest.c
> +++ b/tools/testing/nvdimm/test/ndtest.c
> @@ -693,7 +693,7 @@ static ssize_t flags_show(struct device *dev,
>  	if (seq_buf_used(&s))
>  		seq_buf_printf(&s, "\n");
>  
> -	return seq_buf_used(&s);
> +	return seq_buf_strlen(&s);
>  }
>  static DEVICE_ATTR_RO(flags);
>  
> -- 
> 2.34.1
>