[bug report] drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel

[bug report] drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel

[Dan Carpenter]

Hello Guido Günther,

The patch 72967d5616d3: "drm/panel: Add panel driver for the Mantix
MLAF057WE51-X DSI panel" from Aug 17, 2020, leads to the following
static checker warning:

	drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c:205 mantix_get_modes()
	error: we previously assumed 'mode' could be null (see line 204)

drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
   197  static int mantix_get_modes(struct drm_panel *panel,
   198                              struct drm_connector *connector)
   199  {
   200          struct mantix *ctx = panel_to_mantix(panel);
   201          struct drm_display_mode *mode;
   202  
   203          mode = drm_mode_duplicate(connector->dev, &default_mode);
   204          if (!mode) {
   205                  dev_err(ctx->dev, "Failed to add mode %ux%u@%u\n",
   206                          default_mode.hdisplay, default_mode.vdisplay,
   207                          drm_mode_vrefresh(mode));
                                                  ^^^^
This will lead to a NULL dereference.

   208                  return -ENOMEM;
   209          }
   210  
   211          drm_mode_set_name(mode);
   212  
   213          mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
   214          connector->display_info.width_mm = mode->width_mm;
   215          connector->display_info.height_mm = mode->height_mm;
   216          drm_mode_probed_add(connector, mode);
   217  
   218          return 1;
   219  }

regards,
dan carpenter
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Re: [bug report] drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel

[Guido Günther]

Hi,
On Mon, Aug 31, 2020 at 02:29:24PM +0300, Dan Carpenter wrote:
> Hello Guido Günther,
> 
> The patch 72967d5616d3: "drm/panel: Add panel driver for the Mantix
> MLAF057WE51-X DSI panel" from Aug 17, 2020, leads to the following
> static checker warning:
> 
> 	drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c:205 mantix_get_modes()
> 	error: we previously assumed 'mode' could be null (see line 204)
> 
> drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
>    197  static int mantix_get_modes(struct drm_panel *panel,
>    198                              struct drm_connector *connector)
>    199  {
>    200          struct mantix *ctx = panel_to_mantix(panel);
>    201          struct drm_display_mode *mode;
>    202  
>    203          mode = drm_mode_duplicate(connector->dev, &default_mode);
>    204          if (!mode) {
>    205                  dev_err(ctx->dev, "Failed to add mode %ux%u@%u\n",
>    206                          default_mode.hdisplay, default_mode.vdisplay,
>    207                          drm_mode_vrefresh(mode));
>                                                   ^^^^
> This will lead to a NULL dereference.

Thanks, i'll fold a fix for this into some other upcoming changes to
this driver.
Cheers,
 -- Guido

> 
>    208                  return -ENOMEM;
>    209          }
>    210  
>    211          drm_mode_set_name(mode);
>    212  
>    213          mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
>    214          connector->display_info.width_mm = mode->width_mm;
>    215          connector->display_info.height_mm = mode->height_mm;
>    216          drm_mode_probed_add(connector, mode);
>    217  
>    218          return 1;
>    219  }
> 
> regards,
> dan carpenter
> 
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