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SubjectRe: [RFC PATCH] vhost-vdpa: mark vhost device invalid to reflect vdpa device unregistration
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在 2021/7/5 上午4:52, gautam.dawar@xilinx.com 写道:
> vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> @@ -1091,11 +1122,13 @@ static void vhost_vdpa_remove(struct vdpa_device *vdpa)
> opened = atomic_cmpxchg(&v->opened, 0, 1);
> if (!opened)
> break;
> - wait_for_completion_timeout(&v->completion,
> - msecs_to_jiffies(1000));
> - dev_warn_once(&v->dev,
> - "%s waiting for/dev/%s to be closed\n",
> - __func__, dev_name(&v->dev));
> + if (!wait_for_completion_timeout(&v->completion,
> + msecs_to_jiffies(1000))) {
> + dev_warn(&v->dev,
> + "%s/dev/%s in use, continue..\n",
> + __func__, dev_name(&v->dev));
> + break;
> + }
> } while (1);
>
> put_device(&v->dev);
> + v->dev_invalid = true;


Besides the mapping handling mentioned by Michael. I think this can lead
use-after-free. put_device may release the memory.

Another fundamental issue, vDPA is the parent of vhost-vDPA device. I'm
not sure the device core can allow the parent to go away first.

Thanks


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