[bug report] drm/amdgpu/amdgpu_connectors: remove amdgpu_connector_free_edid

[Dan Carpenter <error27@gmail.com>]

Hello Joshua Peisach,

Commit 71036457ad85 ("drm/amdgpu/amdgpu_connectors: remove
amdgpu_connector_free_edid") from Mar 3, 2026 (linux-next), leads to
the following Smatch static checker warning:

	drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c:1058 amdgpu_connector_dvi_detect()
	warn: passing freed memory 'amdgpu_connector->edid' (line 1048)

drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
    1032                 /* Sometimes the pins required for the DDC probe on DVI
    1033                  * connectors don't make contact at the same time that the ones
    1034                  * for HPD do. If the DDC probe fails even though we had an HPD
    1035                  * signal, try again later
    1036                  */
    1037                 if (!dret && !force &&
    1038                     amdgpu_display_hpd_sense(adev, amdgpu_connector->hpd.hpd)) {
    1039                         DRM_DEBUG_KMS("hpd detected without ddc, retrying in 1 second\n");
    1040                         amdgpu_connector->detected_hpd_without_ddc = true;
    1041                         schedule_delayed_work(&adev->hotplug_work,
    1042                                               msecs_to_jiffies(1000));
    1043                         goto exit;
    1044                 }
    1045         }
    1046         if (dret) {
    1047                 amdgpu_connector->detected_by_load = false;
    1048                 drm_edid_free(amdgpu_connector->edid);
                                       ^^^^^^^^^^^^^^^^^^^^^^
This frees ->edid.  The old code used to set amdgpu_connector->edid = NULL
after freeing it.

    1049                 amdgpu_connector_get_edid(connector);
                                                   ^^^^^^^^^
This function call is supposed to re-assign ->edid but because it's no
longer NULL then it's just a no-op.  (It's so annoying that the naming
switches between amdgpu_connector which and connector which are basically
castings of each other).

    1050 
    1051                 if (!amdgpu_connector->edid) {
    1052                         drm_err(adev_to_drm(adev), "%s: probed a monitor but no|invalid EDID\n",
    1053                                         connector->name);
    1054                         ret = connector_status_connected;
    1055                         broken_edid = true; /* defer use_digital to later */
    1056                 } else {
    1057                         amdgpu_connector->use_digital =
--> 1058                                 drm_edid_is_digital(amdgpu_connector->edid);
                                                             ^^^^^^^^^^^^^^^^^^^^^^
Use after free.

    1059 
    1060                         /* some oems have boards with separate digital and analog connectors

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regards,
dan carpenter