| Message ID | 20210324121832.3714570-1-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/imx: imx-ldb: fix out of bounds array access warning | expand |
On Wed, 2021-03-24 at 13:17 +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. > > The warning could be fixed by adding a Kconfig depedency on CONFIG_OF, > but Liu Ying points out that the driver may hit the out-of-bounds > problem at runtime anyway. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > v2: fix subject line > expand patch description > print mux number > check upper bound as well [] > 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 || mux >= ARRAY_SIZE(ldb->clk_sel)) { > + dev_warn(ldb->dev, "%s: invalid mux %d\n", > + __func__, ERR_PTR(mux)); This does not compile without warnings. drivers/gpu/drm/imx/imx-ldb.c: In function ‘imx_ldb_encoder_enable’: drivers/gpu/drm/imx/imx-ldb.c:201:22: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘void *’ [-Wformat=] 201 | dev_warn(ldb->dev, "%s: invalid mux %d\n", | ^~~~~~~~~~~~~~~~~~~~~~ If you want to use ERR_PTR, the %d should be %pe as ERR_PTR is converting an int a void * to decode the error type and emit it as a string.
On Wed, Mar 24, 2021 at 3:20 PM Joe Perches <joe@perches.com> wrote: > > On Wed, 2021-03-24 at 13:17 +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. > > > > The warning could be fixed by adding a Kconfig depedency on CONFIG_OF, > > but Liu Ying points out that the driver may hit the out-of-bounds > > problem at runtime anyway. > > > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > > --- > > v2: fix subject line > > expand patch description > > print mux number > > check upper bound as well > [] > > 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 || mux >= ARRAY_SIZE(ldb->clk_sel)) { > > + dev_warn(ldb->dev, "%s: invalid mux %d\n", > > + __func__, ERR_PTR(mux)); > > This does not compile without warnings. > > drivers/gpu/drm/imx/imx-ldb.c: In function ‘imx_ldb_encoder_enable’: > drivers/gpu/drm/imx/imx-ldb.c:201:22: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘void *’ [-Wformat=] > 201 | dev_warn(ldb->dev, "%s: invalid mux %d\n", > | ^~~~~~~~~~~~~~~~~~~~~~ > > If you want to use ERR_PTR, the %d should be %pe as ERR_PTR > is converting an int a void * to decode the error type and > emit it as a string. Sorry about that. I decided against using ERR_PTR() in order to also check for positive array overflow, but the version I tested was different from the version I sent. v3 coming. Arnd
On Wed, 2021-03-24 at 17:42 +0100, Arnd Bergmann wrote: > On Wed, Mar 24, 2021 at 3:20 PM Joe Perches <joe@perches.com> wrote: [] > > > 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 || mux >= ARRAY_SIZE(ldb->clk_sel)) { > > > + dev_warn(ldb->dev, "%s: invalid mux %d\n", > > > + __func__, ERR_PTR(mux)); > > > > This does not compile without warnings. > > > > drivers/gpu/drm/imx/imx-ldb.c: In function ‘imx_ldb_encoder_enable’: > > drivers/gpu/drm/imx/imx-ldb.c:201:22: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘void *’ [-Wformat=] > > 201 | dev_warn(ldb->dev, "%s: invalid mux %d\n", > > | ^~~~~~~~~~~~~~~~~~~~~~ > > > > If you want to use ERR_PTR, the %d should be %pe as ERR_PTR > > is converting an int a void * to decode the error type and > > emit it as a string. > > Sorry about that. > > I decided against using ERR_PTR() in order to also check for > positive array overflow, but the version I tested was different from > the version I sent. > > v3 coming. Thanks. No worries. Up to you, vsprintf would emit the positive mux as a funky hashed hex value by default if you use ERR_PTR with mux > ARRAY_SIZE so perhaps %d without the ERR_PTR use makes the most sense.
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c index dbfe39e2f7f6..40310327fa76 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 || mux >= ARRAY_SIZE(ldb->clk_sel)) { + dev_warn(ldb->dev, "%s: invalid mux %d\n", + __func__, ERR_PTR(mux)); + 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 || mux >= ARRAY_SIZE(ldb->clk_sel)) { + dev_warn(ldb->dev, "%s: invalid mux %d\n", + __func__, ERR_PTR(mux)); + return; + } + if (mode->clock > 170000) { dev_warn(ldb->dev, "%s: mode exceeds 170 MHz pixel clock\n", __func__);