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fbdev: sm501: Fix potential divide by zero

Message ID 20250614051100.3501316-1-alexguo1023@gmail.com
State New
Headers show
Series fbdev: sm501: Fix potential divide by zero | expand

Commit Message

Alex Guo June 14, 2025, 5:11 a.m. UTC 
Variable var->pixclock can be set by user. In case it equals to
zero, divide by zero would occur in sm501fb_set_par_common.
Similar crashes have happened in other fbdev drivers.
We cannot find the default vaild value for pixclock for driver
sm501, so we fix this by checking whether 'pixclock' is zero.

Similar commit: commit 16844e58704 ("video: fbdev: tridentfb:
Error out if 'pixclock' equals zero")

Signed-off-by: Alex Guo <alexguo1023@gmail.com>
---
 drivers/video/fbdev/sm501fb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
index ed6f4f43e2d5..a294b4e1c4aa 100644
--- a/drivers/video/fbdev/sm501fb.c
+++ b/drivers/video/fbdev/sm501fb.c
@@ -506,7 +506,9 @@  static int sm501fb_set_par_common(struct fb_info *info,
 			fbi->regs + head_addr);
 
 	/* program CRT clock  */
-
+	
+	if (!var->pixclock)
+		return -EINVAL;
 	pixclock = sm501fb_ps_to_hz(var->pixclock);
 
 	sm501pixclock = sm501_set_clock(fbi->dev->parent, clock_type,