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
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diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
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@@ -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