linux-kernel - Re: [PATCH v2] s390/vfio-ap: fix memory leak in mdev remove callback

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Date:   Wed, 12 May 2021 12:35:03 +0200
From:   Cornelia Huck <cohuck@...hat.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>
Cc:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        borntraeger@...ibm.com, pasic@...ux.vnet.ibm.com,
        jjherne@...ux.ibm.com, jgg@...dia.com, alex.williamson@...hat.com,
        kwankhede@...dia.com, stable@...r.kernel.org,
        Tony Krowiak <akrowiak@...y.rr.com>
Subject: Re: [PATCH v2] s390/vfio-ap: fix memory leak in mdev remove
 callback

On Mon, 10 May 2021 17:48:37 -0400
Tony Krowiak <akrowiak@...ux.ibm.com> wrote:

> The mdev remove callback for the vfio_ap device driver bails out with
> -EBUSY if the mdev is in use by a KVM guest. The intended purpose was
> to prevent the mdev from being removed while in use; however, returning a
> non-zero rc does not prevent removal. This could result in a memory leak
> of the resources allocated when the mdev was created. In addition, the
> KVM guest will still have access to the AP devices assigned to the mdev
> even though the mdev no longer exists.
> 
> To prevent this scenario, cleanup will be done - including unplugging the
> AP adapters, domains and control domains - regardless of whether the mdev
> is in use by a KVM guest or not.
> 
> Fixes: 258287c994de ("s390: vfio-ap: implement mediated device open callback")
> Cc: stable@...r.kernel.org
> Signed-off-by: Tony Krowiak <akrowiak@...y.rr.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c | 13 ++-----------
>  1 file changed, 2 insertions(+), 11 deletions(-)

With the S-o-b fixed,

Reviewed-by: Cornelia Huck <cohuck@...hat.com>