On Thu, Nov 10, 2022 at 02:47:52PM +0100, 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 <[email protected]>
> ---
> drivers/gpu/drm/vc4/vc4_hdmi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index a49f88e5d2b9..6b223a5fcf6f 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -318,8 +318,8 @@ 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_device *drm;
> + struct vc4_hdmi *vc4_hdmi;
Hi, I think this change, or another in this area recently, is causing
the following warning. PTAL
drivers/gpu/drm/vc4/vc4_hdmi.c:351:14: warning: variable 'vc4_hdmi' is
uninitialized when used here [-Wuninitialized]
mutex_lock(&vc4_hdmi->mutex);
^~~~~~~~
drivers/gpu/drm/vc4/vc4_hdmi.c:322:27: note: initialize the variable 'vc4_hdmi'
to silence this warning
struct vc4_hdmi *vc4_hdmi;
^
= NULL
> struct drm_connector_state *conn_state;
> struct drm_crtc_state *crtc_state;
> struct drm_crtc *crtc;
> @@ -330,6 +330,7 @@ static int vc4_hdmi_reset_link(struct drm_connector
> *connector,
> if (!connector)
> return 0;
>
> + drm = connector->dev;
> ret = drm_modeset_lock(&drm->mode_config.connection_mutex, ctx);
> if (ret)
> return ret;
> @@ -347,6 +348,7 @@ static int vc4_hdmi_reset_link(struct drm_connector
> *connector,
> if (!crtc_state->active)
> return 0;
>
> + vc4_hdmi = connector_to_vc4_hdmi(connector);
> if (!vc4_hdmi_supports_scrambling(vc4_hdmi))
> return 0;
>
> --
> 2.25.1
>
>
