[PATCH 2/7] video: fbdev: neofb: Fix the check of 'var->pixclock'

From: Zheyu Ma
Date: Mon Apr 04 2022 - 04:48:21 EST


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:

[ 49.704574] divide error: 0000 [#1] PREEMPT SMP KASAN PTI
[ 49.704593] RIP: 0010:neofb_set_par+0x190f/0x49a0
[ 49.704635] Call Trace:
[ 49.704636] <TASK>
[ 49.704650] fb_set_var+0x604/0xeb0
[ 49.704702] do_fb_ioctl+0x234/0x670
[ 49.704745] fb_ioctl+0xdd/0x130
[ 49.704753] do_syscall_64+0x3b/0x90

Signed-off-by: Zheyu Ma <zheyuma97@xxxxxxxxx>
---
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? */
--
2.25.1