* [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
@ 2022-06-13 16:37 ` Nícolas F. R. A. Prado
0 siblings, 0 replies; 8+ messages in thread
From: Nícolas F. R. A. Prado @ 2022-06-13 16:37 UTC (permalink / raw)
To: Robert Foss
Cc: kernel, AngeloGioacchino Del Regno, Nícolas F. R. A. Prado,
Andrzej Hajda, Daniel Vetter, David Airlie, Hsin-Yi Wang,
Jernej Skrabec, Jonas Karlman, José Expósito,
Laurent Pinchart, Maxime Ripard, Neil Armstrong, Sam Ravnborg,
Thomas Zimmermann, Tzung-Bi Shih, Xin Ji, dri-devel, linux-kernel
While parsing the DT, the anx7625 driver checks for the presence of a
panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
the error pointer and the function returns successfully without first
cleaning that variable. This is an issue since other functions later
check for the presence of a panel bridge by testing the trueness of that
variable.
In order to ensure proper behavior, zero out pdata->panel_bridge before
returning when no panel bridge is found.
Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
---
drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 53a5da6c49dd..3aed4de16690 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev,
pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0);
if (IS_ERR(pdata->panel_bridge)) {
- if (PTR_ERR(pdata->panel_bridge) == -ENODEV)
+ if (PTR_ERR(pdata->panel_bridge) == -ENODEV) {
+ pdata->panel_bridge = NULL;
return 0;
+ }
return PTR_ERR(pdata->panel_bridge);
}
--
2.36.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
2022-06-13 16:37 ` Nícolas F. R. A. Prado
@ 2022-06-13 17:30 ` José Expósito
-1 siblings, 0 replies; 8+ messages in thread
From: José Expósito @ 2022-06-13 17:30 UTC (permalink / raw)
To: Nícolas F. R. A. Prado
Cc: Laurent Pinchart, Andrzej Hajda, Maxime Ripard, Jonas Karlman,
David Airlie, Thomas Zimmermann, dri-devel, Neil Armstrong,
linux-kernel, Robert Foss, Tzung-Bi Shih, Jernej Skrabec,
Hsin-Yi Wang, kernel, Sam Ravnborg, Xin Ji,
AngeloGioacchino Del Regno
On Mon, Jun 13, 2022 at 12:37:05PM -0400, Nícolas F. R. A. Prado wrote:
> While parsing the DT, the anx7625 driver checks for the presence of a
> panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> the error pointer and the function returns successfully without first
> cleaning that variable. This is an issue since other functions later
> check for the presence of a panel bridge by testing the trueness of that
> variable.
>
> In order to ensure proper behavior, zero out pdata->panel_bridge before
> returning when no panel bridge is found.
>
> Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>
> ---
>
> drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 53a5da6c49dd..3aed4de16690 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev,
>
> pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0);
> if (IS_ERR(pdata->panel_bridge)) {
> - if (PTR_ERR(pdata->panel_bridge) == -ENODEV)
> + if (PTR_ERR(pdata->panel_bridge) == -ENODEV) {
> + pdata->panel_bridge = NULL;
> return 0;
> + }
>
> return PTR_ERR(pdata->panel_bridge);
> }
> --
> 2.36.1
>
Thanks for spotting this error Nícolas. As you mentioned, prior to
9e82ea0fb1df the "pdata->panel_bridge" pointer was not modified
(i.e. left to NULL) on the ENODEV error branch.
I missed it during the refactor, sorry about that.
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
@ 2022-06-13 17:30 ` José Expósito
0 siblings, 0 replies; 8+ messages in thread
From: José Expósito @ 2022-06-13 17:30 UTC (permalink / raw)
To: Nícolas F. R. A. Prado
Cc: Robert Foss, kernel, AngeloGioacchino Del Regno, Andrzej Hajda,
Daniel Vetter, David Airlie, Hsin-Yi Wang, Jernej Skrabec,
Jonas Karlman, Laurent Pinchart, Maxime Ripard, Neil Armstrong,
Sam Ravnborg, Thomas Zimmermann, Tzung-Bi Shih, Xin Ji, dri-devel,
linux-kernel
On Mon, Jun 13, 2022 at 12:37:05PM -0400, Nícolas F. R. A. Prado wrote:
> While parsing the DT, the anx7625 driver checks for the presence of a
> panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> the error pointer and the function returns successfully without first
> cleaning that variable. This is an issue since other functions later
> check for the presence of a panel bridge by testing the trueness of that
> variable.
>
> In order to ensure proper behavior, zero out pdata->panel_bridge before
> returning when no panel bridge is found.
>
> Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>
> ---
>
> drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 53a5da6c49dd..3aed4de16690 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev,
>
> pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0);
> if (IS_ERR(pdata->panel_bridge)) {
> - if (PTR_ERR(pdata->panel_bridge) == -ENODEV)
> + if (PTR_ERR(pdata->panel_bridge) == -ENODEV) {
> + pdata->panel_bridge = NULL;
> return 0;
> + }
>
> return PTR_ERR(pdata->panel_bridge);
> }
> --
> 2.36.1
>
Thanks for spotting this error Nícolas. As you mentioned, prior to
9e82ea0fb1df the "pdata->panel_bridge" pointer was not modified
(i.e. left to NULL) on the ENODEV error branch.
I missed it during the refactor, sorry about that.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
2022-06-13 16:37 ` Nícolas F. R. A. Prado
@ 2022-06-14 7:52 ` AngeloGioacchino Del Regno
-1 siblings, 0 replies; 8+ messages in thread
From: AngeloGioacchino Del Regno @ 2022-06-14 7:52 UTC (permalink / raw)
To: Nícolas F. R. A. Prado, Robert Foss
Cc: Andrzej Hajda, Jonas Karlman, David Airlie, Thomas Zimmermann,
dri-devel, Neil Armstrong, linux-kernel, Jernej Skrabec,
Tzung-Bi Shih, Laurent Pinchart, Hsin-Yi Wang,
José Expósito, kernel, Sam Ravnborg, Xin Ji,
Maxime Ripard
Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto:
> While parsing the DT, the anx7625 driver checks for the presence of a
> panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> the error pointer and the function returns successfully without first
> cleaning that variable. This is an issue since other functions later
> check for the presence of a panel bridge by testing the trueness of that
> variable.
>
> In order to ensure proper behavior, zero out pdata->panel_bridge before
> returning when no panel bridge is found.
>
> Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>
I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it.
Besides, good catch!
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
@ 2022-06-14 7:52 ` AngeloGioacchino Del Regno
0 siblings, 0 replies; 8+ messages in thread
From: AngeloGioacchino Del Regno @ 2022-06-14 7:52 UTC (permalink / raw)
To: Nícolas F. R. A. Prado, Robert Foss
Cc: kernel, Andrzej Hajda, Daniel Vetter, David Airlie, Hsin-Yi Wang,
Jernej Skrabec, Jonas Karlman, José Expósito,
Laurent Pinchart, Maxime Ripard, Neil Armstrong, Sam Ravnborg,
Thomas Zimmermann, Tzung-Bi Shih, Xin Ji, dri-devel, linux-kernel
Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto:
> While parsing the DT, the anx7625 driver checks for the presence of a
> panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> the error pointer and the function returns successfully without first
> cleaning that variable. This is an issue since other functions later
> check for the presence of a panel bridge by testing the trueness of that
> variable.
>
> In order to ensure proper behavior, zero out pdata->panel_bridge before
> returning when no panel bridge is found.
>
> Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>
I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it.
Besides, good catch!
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
2022-06-14 7:52 ` AngeloGioacchino Del Regno
@ 2022-06-15 16:04 ` Robert Foss
-1 siblings, 0 replies; 8+ messages in thread
From: Robert Foss @ 2022-06-15 16:04 UTC (permalink / raw)
To: AngeloGioacchino Del Regno
Cc: Andrzej Hajda, Nícolas F. R. A. Prado, Jonas Karlman,
David Airlie, Thomas Zimmermann, dri-devel, Neil Armstrong,
linux-kernel, Jernej Skrabec, Tzung-Bi Shih, Laurent Pinchart,
Hsin-Yi Wang, José Expósito, kernel, Sam Ravnborg,
Xin Ji, Maxime Ripard
On Tue, 14 Jun 2022 at 09:52, AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> wrote:
>
> Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto:
> > While parsing the DT, the anx7625 driver checks for the presence of a
> > panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> > the error pointer and the function returns successfully without first
> > cleaning that variable. This is an issue since other functions later
> > check for the presence of a panel bridge by testing the trueness of that
> > variable.
> >
> > In order to ensure proper behavior, zero out pdata->panel_bridge before
> > returning when no panel bridge is found.
> >
> > Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> >
>
> I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it.
> Besides, good catch!
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>
Applied to drm-misc-next
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/bridge: anx7625: Zero error variable when panel bridge not present
@ 2022-06-15 16:04 ` Robert Foss
0 siblings, 0 replies; 8+ messages in thread
From: Robert Foss @ 2022-06-15 16:04 UTC (permalink / raw)
To: AngeloGioacchino Del Regno
Cc: Nícolas F. R. A. Prado, kernel, Andrzej Hajda, Daniel Vetter,
David Airlie, Hsin-Yi Wang, Jernej Skrabec, Jonas Karlman,
José Expósito, Laurent Pinchart, Maxime Ripard,
Neil Armstrong, Sam Ravnborg, Thomas Zimmermann, Tzung-Bi Shih,
Xin Ji, dri-devel, linux-kernel
On Tue, 14 Jun 2022 at 09:52, AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> wrote:
>
> Il 13/06/22 18:37, Nícolas F. R. A. Prado ha scritto:
> > While parsing the DT, the anx7625 driver checks for the presence of a
> > panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
> > the error pointer and the function returns successfully without first
> > cleaning that variable. This is an issue since other functions later
> > check for the presence of a panel bridge by testing the trueness of that
> > variable.
> >
> > In order to ensure proper behavior, zero out pdata->panel_bridge before
> > returning when no panel bridge is found.
> >
> > Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
> > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> >
>
> I would've preferred s/zero out/cleanup/g but it's also fine as you wrote it.
> Besides, good catch!
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>
Applied to drm-misc-next
^ permalink raw reply [flat|nested] 8+ messages in thread