On 3/19/24 09:13, Roman Smirnov wrote:
The expression htotal * vtotal can have a zero value on
overflow. It is necessary to prevent division by zero like in
fb_var_to_videomode().
Found by Linux Verification Center (linuxtesting.org) with Svace.
Signed-off-by: Roman Smirnov <r.smirnov@xxxxxx>
Reviewed-by: Sergey Shtylyov <s.shtylyov@xxxxxx>
---
V1 -> V2: Replaced the code of the first version with a check.
V2 -> V3: Replaced the code of the second version with a zero check
drivers/video/fbdev/core/fbmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/core/fbmon.c b/drivers/video/fbdev/core/fbmon.c
index 79e5bfbdd34c..ca946919d962 100644
--- a/drivers/video/fbdev/core/fbmon.c
+++ b/drivers/video/fbdev/core/fbmon.c
@@ -1344,7 +1344,7 @@ int fb_videomode_from_videomode(const struct videomode *vm,
vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
vm->vsync_len;
/* prevent division by zero */
- if (htotal && vtotal) {
+ if (htotal && vtotal && (htotal * vtotal)) {
fbmode->refresh = vm->pixelclock / (htotal * vtotal);
I modified your patch like this:
...
- if (htotal && vtotal) {
- fbmode->refresh = vm->pixelclock / (htotal * vtotal);
+ total = htotal * vtotal;
+ if (total) {
+ fbmode->refresh = vm->pixelclock / total;
and added it to the fbdev git tree.
https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/commit/?h=for-next
Thanks,
Helge
