2020-09-18 15:53:05

by Colin King

Subject: [PATCH][next] drm/panel: fix null pointer dereference on pointer mode

From: Colin Ian King <[email protected]>

Currently a null pointer check on pointer mode is passing mode to
function drm_mode_vrefresh and this causes a null pointer dereference
on mode. Fix this by not calling drm_mode_vrefresh since the call
is only required for error reporting.

Addresses-Coverity: ("Dereference after null check")
Fixes: 72967d5616d3 ("drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
index 3482e28e30fc..be4761a643f9 100644
--- a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
+++ b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
@@ -202,9 +202,8 @@ static int mantix_get_modes(struct drm_panel *panel,

mode = drm_mode_duplicate(connector->dev, &default_mode);
if (!mode) {
- dev_err(ctx->dev, "Failed to add mode %ux%u@%u\n",
- default_mode.hdisplay, default_mode.vdisplay,
- drm_mode_vrefresh(mode));
+ dev_err(ctx->dev, "Failed to add mode %ux%u\n",
+ default_mode.hdisplay, default_mode.vdisplay);
return -ENOMEM;
}

--
2.27.0

2020-09-18 16:30:30

by Guido Günther

Subject: Re: [PATCH][next] drm/panel: fix null pointer dereference on pointer mode

Hi,
On Fri, Sep 18, 2020 at 04:51:36PM +0100, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> Currently a null pointer check on pointer mode is passing mode to
> function drm_mode_vrefresh and this causes a null pointer dereference
> on mode. Fix this by not calling drm_mode_vrefresh since the call
> is only required for error reporting.
>
> Addresses-Coverity: ("Dereference after null check")
> Fixes: 72967d5616d3 ("drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
> index 3482e28e30fc..be4761a643f9 100644
> --- a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
> +++ b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
> @@ -202,9 +202,8 @@ static int mantix_get_modes(struct drm_panel *panel,
>
> mode = drm_mode_duplicate(connector->dev, &default_mode);
> if (!mode) {
> - dev_err(ctx->dev, "Failed to add mode %ux%u@%u\n",
> - default_mode.hdisplay, default_mode.vdisplay,
> - drm_mode_vrefresh(mode));
> + dev_err(ctx->dev, "Failed to add mode %ux%u\n",
> + default_mode.hdisplay, default_mode.vdisplay);
> return -ENOMEM;
> }

drm_mode_vrefresh(&default_mode) gives some more clue what's going on -
I have had a fix queued up in my tree already but if you send a v2
that's fine.

Thanks!
-- Guido

>
> --
> 2.27.0
>

2020-09-18 16:43:59

by Colin King

Subject: Re: [PATCH][next] drm/panel: fix null pointer dereference on pointer mode

On 18/09/2020 17:22, Guido Günther wrote:
> Hi,
> On Fri, Sep 18, 2020 at 04:51:36PM +0100, Colin King wrote:
>> From: Colin Ian King <[email protected]>
>>
>> Currently a null pointer check on pointer mode is passing mode to
>> function drm_mode_vrefresh and this causes a null pointer dereference
>> on mode. Fix this by not calling drm_mode_vrefresh since the call
>> is only required for error reporting.
>>
>> Addresses-Coverity: ("Dereference after null check")
>> Fixes: 72967d5616d3 ("drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c | 5 ++---
>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
>> index 3482e28e30fc..be4761a643f9 100644
>> --- a/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
>> +++ b/drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
>> @@ -202,9 +202,8 @@ static int mantix_get_modes(struct drm_panel *panel,
>>
>> mode = drm_mode_duplicate(connector->dev, &default_mode);
>> if (!mode) {
>> - dev_err(ctx->dev, "Failed to add mode %ux%u@%u\n",
>> - default_mode.hdisplay, default_mode.vdisplay,
>> - drm_mode_vrefresh(mode));
>> + dev_err(ctx->dev, "Failed to add mode %ux%u\n",
>> + default_mode.hdisplay, default_mode.vdisplay);
>> return -ENOMEM;
>> }
>
> drm_mode_vrefresh(&default_mode) gives some more clue what's going on -
> I have had a fix queued up in my tree already but if you send a v2
> that's fine.

I'll defer to your queued up fix.
>
> Thanks!
> -- Guido
>
>>
>> --
>> 2.27.0
>>