On Thu, 2017-08-24 at 14:04 +0300, Dan Carpenter wrote:
> Hello Bart Van Assche,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 7277cc67b391: "skd: Avoid that module unloading triggers a
> use-after-free" from Aug 17, 2017, leads to the following Smatch
> complaint:
>
> drivers/block/skd_main.c:3080 skd_free_disk()
> error: we previously assumed 'disk' could be null (see line 3074)
>
> drivers/block/skd_main.c
> 3073
> 3074 if (disk && (disk->flags & GENHD_FL_UP))
> ^^^^
> Existing code checked for NULL. The new code shuffles things around.
>
> 3075 del_gendisk(disk);
> 3076
> 3077 if (skdev->queue) {
> 3078 blk_cleanup_queue(skdev->queue);
> 3079 skdev->queue = NULL;
> 3080 disk->queue = NULL;
> ^^^^^^^^^^^
> Now we don't check here.
>
> 3081 }
> 3082
>
> regards,
> dan carpenter
Hello Dan,
If you have a look at skd_cons_disk() you will see that skdev->queue != NULL
implies that skdev->disk != NULL. So I think the above report is a false
positive.
Bart.
