Re: [PATCH] drm: zynqmp_dp: Fix uninitialized variable in debugfs()
Sean Anderson <[email protected]>
| Newsgroups | org.kernel.vger.kernel-janitors,org.freedesktop.lists.dri-devel,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On 5/25/26 03:16, Dan Carpenter wrote:
> If the *ppos is non-zero then simple_write_to_buffer() will not
> initialize the start of the buf[] buffer. It doesn't really make sense
> to allow non-zero values for *ppos, so check for that at the start and
> return -EINVAL.
non-zero ppos seems to be handled properly by simple_write_to_buffer.
--Sean
> Fixes: 28edaacb821c ("drm: zynqmp_dp: Add debugfs interface for compliance testing")
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> drivers/gpu/drm/xlnx/zynqmp_dp.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 7fb11b0a44f0..847179476041 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -1888,6 +1888,9 @@ static ssize_t zynqmp_dp_pattern_write(struct file *file,
> ssize_t ret;
> int pattern;
>
> + if (*ppos != 0)
> + return -EINVAL;
> +
> ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf,
> count);
> if (ret < 0)
> @@ -2028,6 +2031,9 @@ static ssize_t zynqmp_dp_custom_write(struct file *file,
> ssize_t ret;
> char buf[sizeof(dp->test.custom)];
>
> + if (*ppos != 0)
> + return -EINVAL;
> +
> ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count);
> if (ret < 0)
> return ret;