From 5b8d3577acdf5e7b1b32643fd4374d3993a238cd Mon Sep 17 00:00:00 2001
From: Zheyu Ma <zheyuma97@gmail.com>
Date: Mon, 4 Apr 2022 16:47:18 +0800
Subject: video: fbdev: neofb: Fix the check of 'var->pixclock'
Git-commit: 85ec038b53faec11baefb2c42b6c0ce8bec94d3e
Patch-mainline: v5.18-rc5
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
The previous check against 'var->pixclock' doesn't return -EINVAL when
it equals zero, but the driver uses it again, causing the divide error.
Fix this by returning when 'var->pixclock' is zero.
The following log reveals it:
divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:neofb_set_par+0x190f/0x49a0
Call Trace:
<TASK>
fb_set_var+0x604/0xeb0
do_fb_ioctl+0x234/0x670
fb_ioctl+0xdd/0x130
do_syscall_64+0x3b/0x90
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/video/fbdev/neofb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/neofb.c b/drivers/video/fbdev/neofb.c
index 966df2a07360..28d32cbf496b 100644
--- a/drivers/video/fbdev/neofb.c
+++ b/drivers/video/fbdev/neofb.c
@@ -585,7 +585,7 @@ neofb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
DBG("neofb_check_var");
- if (var->pixclock && PICOS2KHZ(var->pixclock) > par->maxClock)
+ if (!var->pixclock || PICOS2KHZ(var->pixclock) > par->maxClock)
return -EINVAL;
/* Is the mode larger than the LCD panel? */
--
2.38.1