static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
			  unsigned long arg)
{
	struct fb_cmap_user __user *cmap;
	struct fb_cmap32 __user *cmap32;
	__u32 data;
	int err;

	cmap = compat_alloc_user_space(sizeof(*cmap));
	cmap32 = compat_ptr(arg);

	if (copy_in_user(&cmap->start, &cmap32->start, 2 * sizeof(__u32)))
		return -EFAULT;

	if (get_user(data, &cmap32->red) ||
	    put_user(compat_ptr(data), &cmap->red) ||
	    get_user(data, &cmap32->green) ||
	    put_user(compat_ptr(data), &cmap->green) ||
	    get_user(data, &cmap32->blue) ||
	    put_user(compat_ptr(data), &cmap->blue) ||
	    get_user(data, &cmap32->transp) ||
	    put_user(compat_ptr(data), &cmap->transp))
		return -EFAULT;

	err = do_fb_ioctl(info, cmd, (unsigned long) cmap);

	if (!err) {
		if (copy_in_user(&cmap32->start,
				 &cmap->start,
				 2 * sizeof(__u32)))
			err = -EFAULT;
	}
	return err;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.