fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

[PATCH] fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

Posted by Greg Kroah-Hartman 2 months, 1 week ago

Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
by zero error"), we also need to prevent that same crash from happening
in the udlfb driver as it uses pixclock directly when dividing, which
will crash.

Cc: Helge Deller <deller@gmx.de>
Assisted-by: gregkh_clanker_t1000
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/video/fbdev/tdfxfb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fbdev/tdfxfb.c b/drivers/video/fbdev/tdfxfb.c
index 51ebe78359ec..531fb8478e20 100644
--- a/drivers/video/fbdev/tdfxfb.c
+++ b/drivers/video/fbdev/tdfxfb.c
@@ -496,6 +496,9 @@ static int tdfxfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
 		}
 	}
 
+	if (!var->pixclock)
+		return -EINVAL;
+
 	if (PICOS2KHZ(var->pixclock) > par->max_pixclock) {
 		DPRINTK("pixclock too high (%ldKHz)\n",
 			PICOS2KHZ(var->pixclock));
-- 
2.53.0

Re: [PATCH] fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

Posted by Helge Deller 2 months, 1 week ago

On 4/9/26 15:23, Greg Kroah-Hartman wrote:
> Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
> by zero error"), we also need to prevent that same crash from happening
> in the udlfb driver as it uses pixclock directly when dividing, which
> will crash.
> 
> Cc: Helge Deller <deller@gmx.de>
> Assisted-by: gregkh_clanker_t1000
> Cc: stable <stable@kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>   drivers/video/fbdev/tdfxfb.c | 3 +++
>   1 file changed, 3 insertions(+)

applied.

Thanks!
Helge