Hi,
On Sat, Oct 29, 2022 at 11:34:13AM +0200, José Expósito wrote:
> Commit 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link on hotplug") introduced
> the vc4_hdmi_reset_link() function. This function dereferences the
> "connector" pointer before checking whether it is NULL or not.
>
> Rework variable assignment to avoid this issue.
>
> Fixes: 6bed2ea3cb38 ("drm/vc4: hdmi: Reset link on hotplug")
> Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx>
> ---
> drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 4a73fafca51b..07d058b6afb7 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -319,9 +319,9 @@ static int reset_pipe(struct drm_crtc *crtc,
> static int vc4_hdmi_reset_link(struct drm_connector *connector,
> struct drm_modeset_acquire_ctx *ctx)
> {
> - struct drm_device *drm = connector->dev;
> - struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
> - struct drm_encoder *encoder = &vc4_hdmi->encoder.base;
> + struct drm_device *drm;
> + struct vc4_hdmi *vc4_hdmi;
> + struct drm_encoder *encoder;
> struct drm_connector_state *conn_state;
> struct drm_crtc_state *crtc_state;
> struct drm_crtc *crtc;
> @@ -332,6 +332,10 @@ static int vc4_hdmi_reset_link(struct drm_connector *connector,
> if (!connector)
> return 0;
>
> + drm = connector->dev;
> + vc4_hdmi = connector_to_vc4_hdmi(connector);
> + encoder = &vc4_hdmi->encoder.base;
> +
I don't think that's right. Connector shouldn't be NULL to begin with,
how did you notice this?
Maxime
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