From: Wei Chen <harperchen1110@gmail.com>
Date: Wed, 15 Mar 2023 09:22:54 +0000 (+0000)
Subject: fbdev: au1200fb: Fix potential divide by zero
X-Git-Tag: baikal/mips/sdk5.8.2~36
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=aa2df0785e6a98d5799da07a9d946f8f32681380;p=kernel.git

fbdev: au1200fb: Fix potential divide by zero

[ Upstream commit 44a3b36b42acfc433aaaf526191dd12fbb919fdb ]

var->pixclock can be assigned to zero by user. Without
proper check, divide by zero would occur when invoking
macro PICOS2KHZ in au1200fb_fb_check_var.

Error out if var->pixclock is zero.

Signed-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/video/fbdev/au1200fb.c b/drivers/video/fbdev/au1200fb.c
index 265d3b45efd0c..43a4dddaafd52 100644
--- a/drivers/video/fbdev/au1200fb.c
+++ b/drivers/video/fbdev/au1200fb.c
@@ -1040,6 +1040,9 @@ static int au1200fb_fb_check_var(struct fb_var_screeninfo *var,
 	u32 pixclock;
 	int screen_size, plane;
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	plane = fbdev->plane;
 
 	/* Make sure that the mode respect all LCD controller and