linux-kernel - [PATCH 1/1] media: ccs: Avoid possible division by zero

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Message-ID: <20251124230045.3188417-1-sakari.ailus@linux.intel.com>
Date: Tue, 25 Nov 2025 01:00:45 +0200
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: linux-media@...r.kernel.org
Cc: Nathan Chancellor <nathan@...nel.org>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] media: ccs: Avoid possible division by zero

Calculating maximum M for scaler configuration involves dividing by
MIN_X_OUTPUT_SIZE limit register's value. Albeit the value is presumably
non-zero, the driver was missing the check it in fact was. Fix this.

Reported-by: Josh Poimboeuf <jpoimboe@...nel.org>
Closes: https://lore.kernel.org/all/ahukd6b3wonye3zgtptvwzvrxldcruazs2exfvll6etjhmcxyj@vq3eh6pd375b/
Fixes: ccfc97bdb5ae ("[media] smiapp: Add driver")
Cc: stable@...r.kernel.org # for 5.15 and later
Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
---
Not tested but what could go wrong here? :-)

 drivers/media/i2c/ccs/ccs-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index f8523140784c..dadff8c50679 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -2346,7 +2346,7 @@ static void ccs_set_compose_scaler(struct v4l2_subdev *subdev,
 		* CCS_LIM(sensor, SCALER_N_MIN) / sel->r.height;
 	max_m = crops[CCS_PAD_SINK]->width
 		* CCS_LIM(sensor, SCALER_N_MIN)
-		/ CCS_LIM(sensor, MIN_X_OUTPUT_SIZE);
+		/ (CCS_LIM(sensor, MIN_X_OUTPUT_SIZE) ?: 1);
 
 	a = clamp(a, CCS_LIM(sensor, SCALER_M_MIN),
 		  CCS_LIM(sensor, SCALER_M_MAX));
-- 
2.47.3