Re: [PATCH] drm/imx: fix out of bounds array access warning
Hi Arnd,
Thanks for your patch.
It would be good to improve the patch's head line to something like:
drm/imx: imx-ldb: fix out of bounds array access warning
Regards,
Liu Ying
On Tue, 2021-03-23 at 14:05 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann
>
> When CONFIG_OF is disabled, building with 'make W=1' produces warnings
> about out of bounds array access:
>
> drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop':
> drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below
> array bounds of 'struct clk *[4]' [-Werror=array-bounds]
>
> Add an error check before the index is used, which helps with the
> warning, as well as any possible other error condition that may be
> triggered at runtime.
>
> Signed-off-by: Arnd Bergmann
> ---
> drivers/gpu/drm/imx/imx-ldb.c | 12
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
> index dbfe39e2f7f6..1210360cec8a 100644
> --- a/drivers/gpu/drm/imx/imx-ldb.c
> +++ b/drivers/gpu/drm/imx/imx-ldb.c
> @@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder
> *encoder)
> int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
> int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
>
> + if (mux < 0) {
> + dev_warn(ldb->dev,
> + "%s: invalid mux\n", __func__);
> + return;
> + }
> +
> drm_panel_prepare(imx_ldb_ch->panel);
>
> if (dual) {
> @@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder
> *encoder,
> int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
> u32 bus_format = imx_ldb_ch->bus_format;
>
> + if (mux < 0) {
> + dev_warn(ldb->dev,
> + "%s: invalid mux\n", __func__);
> + return;
> + }
> +
> if (mode->clock > 17) {
> dev_warn(ldb->dev,
>"%s: mode exceeds 170 MHz pixel clock\n", __func__);
Re: [PATCH] drm/imx: fix out of bounds array access warning
Hi Fabio, On Tue, 2021-03-23 at 11:02 -0300, Fabio Estevam wrote: > Hi Arnd, > > On Tue, Mar 23, 2021 at 10:05 AM Arnd Bergmann wrote: > > From: Arnd Bergmann > > > > When CONFIG_OF is disabled, building with 'make W=1' produces warnings > > about out of bounds array access: > > > > drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop': > > drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below > > array bounds of 'struct clk *[4]' [-Werror=array-bounds] > > What about making the driver depend on OF instead (like it is done in > DRM_IMX_HDMI) ? The below patch made DRM_IMX_HDMI depend on OF, because of_drm_find_bridge() is not defined when OF is disabled. drm/imx: dw_hdmi-imx: depend on OF to fix randconfig compile tests on x86_64 It doesn't look like DRM_IMX_LDB is in the same case. Moreover, even if OF is enabled, drm_of_encoder_active_endpoint() is likely to return -EINVAL. So, it looks ok to add an error check. Regards, Liu Ying > > --- a/drivers/gpu/drm/imx/Kconfig > +++ b/drivers/gpu/drm/imx/Kconfig > @@ -27,7 +27,7 @@ config DRM_IMX_TVE > > config DRM_IMX_LDB > tristate "Support for LVDS displays" > - depends on DRM_IMX && MFD_SYSCON > + depends on DRM_IMX && MFD_SYSCON && OF > depends on COMMON_CLK > select DRM_PANEL > help
Re: [PATCH] drm/imx: fix out of bounds array access warning
On Tue, 2021-03-23 at 07:19 -0700, Joe Perches wrote:
> On Tue, 2021-03-23 at 14:05 +0100, Arnd Bergmann wrote:
> > From: Arnd Bergmann
> >
> > When CONFIG_OF is disabled, building with 'make W=1' produces warnings
> > about out of bounds array access:
> >
> > drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop':
> > drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below
> > array bounds of 'struct clk *[4]' [-Werror=array-bounds]
> >
> > Add an error check before the index is used, which helps with the
> > warning, as well as any possible other error condition that may be
> > triggered at runtime.
> []
> > diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
> []
> > @@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder
> > *encoder)
> > int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
> > int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
> >
> > + if (mux < 0) {
> > + dev_warn(ldb->dev,
> > +"%s: invalid mux\n", __func__);
>
> trivia:
>
> Any real reason to make this 2 lines? It fits nicely in 80 chars. Maybe:
>
> dev_warn(ldb->dev, "%s: invalid mux: %d\n", __func__, mux);
>
> or maybe:
>
> dev_warn(ldb->dev, "%s: invalid mux: %pe\n",
>__func__, ERR_PTR(mux));
+1
The second one looks better as it's more informative.
Regards,
Liu Ying
>
> > @@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder
> > *encoder,
> []
> > + if (mux < 0) {
> > + dev_warn(ldb->dev,
> > +"%s: invalid mux\n", __func__);
>
> etc...
>
>
Re: [PATCH] drm/imx: fix out of bounds array access warning
On Tue, 2021-03-23 at 14:05 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann
>
> When CONFIG_OF is disabled, building with 'make W=1' produces warnings
> about out of bounds array access:
>
> drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop':
> drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below
> array bounds of 'struct clk *[4]' [-Werror=array-bounds]
>
> Add an error check before the index is used, which helps with the
> warning, as well as any possible other error condition that may be
> triggered at runtime.
[]
> diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
[]
> @@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder
> *encoder)
> int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
> int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
>
> + if (mux < 0) {
> + dev_warn(ldb->dev,
> + "%s: invalid mux\n", __func__);
trivia:
Any real reason to make this 2 lines? It fits nicely in 80 chars. Maybe:
dev_warn(ldb->dev, "%s: invalid mux: %d\n", __func__, mux);
or maybe:
dev_warn(ldb->dev, "%s: invalid mux: %pe\n",
__func__, ERR_PTR(mux));
> @@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder
> *encoder,
[]
> + if (mux < 0) {
> + dev_warn(ldb->dev,
> + "%s: invalid mux\n", __func__);
etc...
Re: [PATCH] drm/imx: fix out of bounds array access warning
Hi Arnd, On Tue, Mar 23, 2021 at 10:05 AM Arnd Bergmann wrote: > > From: Arnd Bergmann > > When CONFIG_OF is disabled, building with 'make W=1' produces warnings > about out of bounds array access: > > drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop': > drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below > array bounds of 'struct clk *[4]' [-Werror=array-bounds] What about making the driver depend on OF instead (like it is done in DRM_IMX_HDMI) ? --- a/drivers/gpu/drm/imx/Kconfig +++ b/drivers/gpu/drm/imx/Kconfig @@ -27,7 +27,7 @@ config DRM_IMX_TVE config DRM_IMX_LDB tristate "Support for LVDS displays" - depends on DRM_IMX && MFD_SYSCON + depends on DRM_IMX && MFD_SYSCON && OF depends on COMMON_CLK select DRM_PANEL help
[PATCH] drm/imx: fix out of bounds array access warning
From: Arnd Bergmann
When CONFIG_OF is disabled, building with 'make W=1' produces warnings
about out of bounds array access:
drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop':
drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below array
bounds of 'struct clk *[4]' [-Werror=array-bounds]
Add an error check before the index is used, which helps with the
warning, as well as any possible other error condition that may be
triggered at runtime.
Signed-off-by: Arnd Bergmann
---
drivers/gpu/drm/imx/imx-ldb.c | 12
1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index dbfe39e2f7f6..1210360cec8a 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -197,6 +197,12 @@ static void imx_ldb_encoder_enable(struct drm_encoder
*encoder)
int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
+ if (mux < 0) {
+ dev_warn(ldb->dev,
+"%s: invalid mux\n", __func__);
+ return;
+ }
+
drm_panel_prepare(imx_ldb_ch->panel);
if (dual) {
@@ -255,6 +261,12 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder
*encoder,
int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
u32 bus_format = imx_ldb_ch->bus_format;
+ if (mux < 0) {
+ dev_warn(ldb->dev,
+"%s: invalid mux\n", __func__);
+ return;
+ }
+
if (mode->clock > 17) {
dev_warn(ldb->dev,
"%s: mode exceeds 170 MHz pixel clock\n", __func__);
--
2.29.2
