Re: [PATCH v3 10/11] nvdimm: ndtest: Return the string length from flags_show()
From: Alison Schofield
Date: Thu Oct 01 2026 - 19:40:23 EST
On Wed, Sep 30, 2026 at 10:40:47PM -0700, Alison Schofield wrote:
> 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?
NVM, found my answer when trying to build without the entire series.
Tagging but won't try to merge -
Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>
>
> -- 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
> >
>