drm/imx: imx-ldb: fix out of bounds array access warning
Subsystems (3)
PATCH v3 1/1 drm/imx: imx-ldb: fix out of bounds array access warning
From: Arnd Bergmann <[email protected]>
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.
---
v3: fix build regression from v2
v2: fix subject line
expand patch description
print mux number
check upper bound as well
--- drivers/gpu/drm/imx/imx-ldb.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
drivers/gpu/drm/imx/imx-ldb.c +10 -0
@@ -197,6 +197,11 @@ 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__, mux); +return ; + } +drm_panel_prepare (imx_ldb_ch->panel);if (dual) {
@@ -255,6 +260,11 @@ 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__, mux); +return ; + } +if (mode->clock >170000 ) {dev_warn (ldb->dev,"%s: mode exceeds 170 MHz pixel clock\n" , __func__);
Signature · 6 lines
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Quoted 8 lines · Arnd Bergmann
From: Arnd Bergmann <[email protected]>
When
CONFIG_OFis 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]
Quoted 7 lines
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
Kconfigdepedency onCONFIG_OF, but Liu Ying points out that the driver may hit the out-of-bounds problem at runtime anyway.
Almost impossible to hit the out-of-bounds problem at runtime, unless something wrong happens and makes unexpected parameters(node and/or encoder) be handed over to drm_of_encoder_active_port_id(). Anyway, an error check on return value from drm_of_encoder_active_port_id() looks ok to me.
Quoted 2 lines
Signed-off-by Arnd Bergmann <[email protected]>
Thanks,
Liu Ying
Quoted 28 lines
---
v3: fix build regression from v2
v2: fix subject line
expand patch description
print mux number
check upper bound as well--- drivers/gpu/drm/imx/imx-ldb.c | 10 ++++++++++ 1 file changed, 10 insertions(+)drivers/gpu/drm/imx/imx-ldb.c +5
-0@@ -197,6 +197,11 @@ 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__, mux); +return ; + } +drm_panel_prepare (imx_ldb_ch->panel);if (dual) {@@ -255,6 +260,11 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder,int mux =drm_of_encoder_active_port_id (imx_ldb_ch->child, encoder);
drivers/gpu/drm/imx/imx-ldb.c imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder, · line 270
Quoted 10 lines
drivers/gpu/drm/imx/imx-ldb.c +5
-0u32 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__, mux); +return ; + } +if (mode->clock >170000 ) {dev_warn (ldb->dev,"%s: mode exceeds 170 MHz pixel clock\n" , __func__);
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Philipp Zabel
AppliedQuoted 13 lines · Liu Ying
Quoted 12 lines · Arnd Bergmann
From: Arnd Bergmann <[email protected]>
When
CONFIG_OFis 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.
Quoted 6 lines
Quoted 5 lines
The warning could be fixed by adding a
Kconfigdepedency onCONFIG_OF, but Liu Ying points out that the driver may hit the out-of-bounds problem at runtime anyway.Signed-off-by Arnd Bergmann <[email protected]>Reviewed-by Liu Ying <[email protected]>
Thank you, applied to imx-drm/fixes.
regards
Philipp
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