| Message ID | 20210323130550.2289487-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/imx: fix out of bounds array access warning | expand |
Hi Arnd, On Tue, Mar 23, 2021 at 10:05 AM Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > 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
On Tue, 2021-03-23 at 14:05 +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@arndb.de> > > 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...
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 <arnd@arndb.de> > > > > 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... > >
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 <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > > > 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
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 <arnd@arndb.de> > > 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 <arnd@arndb.de> > --- > 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 > 170000) { > dev_warn(ldb->dev, > "%s: mode exceeds 170 MHz pixel clock\n", __func__);
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 > 170000) { dev_warn(ldb->dev, "%s: mode exceeds 170 MHz pixel clock\n", __func__);