From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>,
linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: cohuck@redhat.com, pasic@linux.vnet.ibm.com,
jjherne@linux.ibm.com, jgg@nvidia.com,
alex.williamson@redhat.com, kwankhede@nvidia.com,
stable@vger.kernel.org, Vasily Gorbik <gor@linux.ibm.com>
Subject: Re: [PATCH v2] s390/vfio-ap: fix memory leak in mdev remove callback
Date: Wed, 12 May 2021 18:49:23 +0200 [thread overview]
Message-ID: <834f95f8-c1ca-17da-b709-69d5c55e8fcd@de.ibm.com> (raw)
In-Reply-To: <20210510214837.359717-1-akrowiak@linux.ibm.com>
On 10.05.21 23:48, Tony Krowiak 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@vger.kernel.org
> Signed-off-by: Tony Krowiak <akrowiak@stny.rr.com>
applied to the internal s390 tree. Lets give it some days of testing coverage of
CI and others.
Vasily, can you add this for the s390/fixes branch early next week if nothing
goes wrong?
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 13 ++-----------
> 1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index b2c7e10dfdcd..f90c9103dac2 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -26,6 +26,7 @@
>
> static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
> static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
> +static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev);
>
> static int match_apqn(struct device *dev, const void *data)
> {
> @@ -366,17 +367,7 @@ static int vfio_ap_mdev_remove(struct mdev_device *mdev)
> struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>
> mutex_lock(&matrix_dev->lock);
> -
> - /*
> - * If the KVM pointer is in flux or the guest is running, disallow
> - * un-assignment of control domain.
> - */
> - if (matrix_mdev->kvm_busy || matrix_mdev->kvm) {
> - mutex_unlock(&matrix_dev->lock);
> - return -EBUSY;
> - }
> -
> - vfio_ap_mdev_reset_queues(mdev);
> + vfio_ap_mdev_unset_kvm(matrix_mdev);
> list_del(&matrix_mdev->node);
> kfree(matrix_mdev);
> mdev_set_drvdata(mdev, NULL);
>
next prev parent reply other threads:[~2021-05-12 17:06 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-10 21:48 [PATCH v2] s390/vfio-ap: fix memory leak in mdev remove callback Tony Krowiak
2021-05-10 21:56 ` Tony Krowiak
2021-05-12 10:35 ` Cornelia Huck
2021-05-12 12:41 ` Jason Gunthorpe
2021-05-12 15:32 ` Christian Borntraeger
2021-05-12 16:50 ` Jason Gunthorpe
2021-05-13 14:19 ` Tony Krowiak
2021-05-13 14:18 ` Tony Krowiak
2021-05-13 17:25 ` Jason Gunthorpe
2021-05-13 17:32 ` Halil Pasic
2021-05-13 17:34 ` Jason Gunthorpe
2021-05-12 16:49 ` Christian Borntraeger [this message]
2021-05-12 18:35 ` Halil Pasic
2021-05-13 14:35 ` Tony Krowiak
2021-05-13 17:45 ` Halil Pasic
2021-05-13 19:23 ` Tony Krowiak
2021-05-14 0:15 ` Halil Pasic
2021-05-17 13:37 ` Tony Krowiak
2021-05-17 19:10 ` Halil Pasic
2021-05-18 9:30 ` Christian Borntraeger
2021-05-18 13:42 ` Tony Krowiak
2021-05-18 13:59 ` Christian Borntraeger
2021-05-18 15:33 ` Halil Pasic
2021-05-18 17:01 ` Christian Borntraeger
2021-05-18 23:27 ` Halil Pasic
2021-05-19 8:17 ` Christian Borntraeger
2021-05-19 11:22 ` Christian Borntraeger
2021-05-19 12:59 ` Halil Pasic
2021-05-19 13:02 ` Jason Gunthorpe
2021-05-19 11:25 ` Halil Pasic
2021-05-18 18:14 ` Tony Krowiak
2021-05-18 18:22 ` Christian Borntraeger
2021-05-18 18:40 ` Tony Krowiak
2021-05-18 13:41 ` Tony Krowiak
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