diff mbox series

[4.4,35/38] drm/imx: imx-ldb: fix out of bounds array access warning

Message ID 20210415144414.492206846@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman April 15, 2021, 2:47 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>


[ Upstream commit 33ce7f2f95cabb5834cf0906308a5cb6103976da ]

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>

Reviewed-by: Liu Ying <victor.liu@nxp.com>

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Signed-off-by: Sasha Levin <sashal@kernel.org>

---
 drivers/gpu/drm/imx/imx-ldb.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

-- 
2.30.2
diff mbox series

Patch

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index b9dc2ef64ed8..74585ba16501 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -217,6 +217,11 @@  static void imx_ldb_encoder_commit(struct drm_encoder *encoder)
 	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
 	int mux = imx_drm_encoder_get_mux_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) {
@@ -267,6 +272,11 @@  static void imx_ldb_encoder_mode_set(struct drm_encoder *encoder,
 	unsigned long di_clk = mode->clock * 1000;
 	int mux = imx_drm_encoder_get_mux_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;
+	}
+
 	if (mode->clock > 170000) {
 		dev_warn(ldb->dev,
 			 "%s: mode exceeds 170 MHz pixel clock\n", __func__);