From fd50ab7dd4ee5bbb4aebffa76ae18484b03a8ea5 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 9 Apr 2026 15:23:46 +0200 Subject: [PATCH] fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO commit a31e4518bec70333a0a98f2946a12b53b45fe5b9 upstream. 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: Bernie Thompson Cc: Helge Deller Fixes: 59277b679f8b ("Staging: udlfb: add dynamic modeset support") Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/udlfb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index 12bd5a7318e1..7b221164dd95 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -1077,6 +1077,9 @@ static int dlfb_ops_check_var(struct fb_var_screeninfo *var, struct fb_videomode mode; struct dlfb_data *dlfb = info->par; + if (!var->pixclock) + return -EINVAL; + /* set device-specific elements of var unrelated to mode */ dlfb_var_color_format(var);