[PATCH RESEND] drm/mediatek/dp: fix spurious kfree()

[PATCH RESEND] drm/mediatek/dp: fix spurious kfree()

[Michael Walle]

drm_edid_to_sad() might return an error or just zero. If that is the
case, we must not free the SADs because there was no allocation in
the first place.

Fixes: dab12fa8d2bd ("drm/mediatek/dp: fix memory leak on ->get_edid callback audio detection")
Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/mediatek/mtk_dp.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 536366956447..ada12927bbac 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -2073,9 +2073,15 @@ static const struct drm_edid *mtk_dp_edid_read(struct drm_bridge *bridge,
 		 */
 		const struct edid *edid = drm_edid_raw(drm_edid);
 		struct cea_sad *sads;
+		int ret;
 
-		audio_caps->sad_count = drm_edid_to_sad(edid, &sads);
-		kfree(sads);
+		ret = drm_edid_to_sad(edid, &sads);
+		/* Ignore any errors */
+		if (ret < 0)
+			ret = 0;
+		if (ret)
+			kfree(sads);
+		audio_caps->sad_count = ret;
 
 		/*
 		 * FIXME: This should use connector->display_info.has_audio from
-- 
2.39.2

Re: [PATCH RESEND] drm/mediatek/dp: fix spurious kfree()

[Chun-Kuang Hu]

Hi, Michael:

Michael Walle <mwalle@kernel.org> 於 2024年6月4日 週二 下午4:33寫道：
>
> drm_edid_to_sad() might return an error or just zero. If that is the
> case, we must not free the SADs because there was no allocation in
> the first place.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

>
> Fixes: dab12fa8d2bd ("drm/mediatek/dp: fix memory leak on ->get_edid callback audio detection")
> Signed-off-by: Michael Walle <mwalle@kernel.org>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 536366956447..ada12927bbac 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -2073,9 +2073,15 @@ static const struct drm_edid *mtk_dp_edid_read(struct drm_bridge *bridge,
>                  */
>                 const struct edid *edid = drm_edid_raw(drm_edid);
>                 struct cea_sad *sads;
> +               int ret;
>
> -               audio_caps->sad_count = drm_edid_to_sad(edid, &sads);
> -               kfree(sads);
> +               ret = drm_edid_to_sad(edid, &sads);
> +               /* Ignore any errors */
> +               if (ret < 0)
> +                       ret = 0;
> +               if (ret)
> +                       kfree(sads);
> +               audio_caps->sad_count = ret;
>
>                 /*
>                  * FIXME: This should use connector->display_info.has_audio from
> --
> 2.39.2
>