On Thu, Aug 24, 2017 at 03:04:12PM +0000, Bart Van Assche wrote:
> 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.
>
Oh, yeah. You're right. Thanks for taking a look at this.
regards,
dan carpenter
