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Fri, 21 May 2021 19:36:53 +0000 (GMT) Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3A7F86E04C; Fri, 21 May 2021 19:36:52 +0000 (GMT) Received: from cpe-172-100-179-72.stny.res.rr.com (unknown [9.85.177.219]) by b03ledav001.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 21 May 2021 19:36:52 +0000 (GMT) From: Tony Krowiak To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Cc: borntraeger@de.ibm.com, cohuck@redhat.com, pasic@linux.vnet.ibm.com, jjherne@linux.ibm.com, jgg@nvidia.com, alex.williamson@redhat.com, kwankhede@nvidia.com, frankja@linux.ibm.com, david@redhat.com, imbrenda@linux.ibm.com, hca@linux.ibm.com Subject: [PATCH v4 1/2] s390/vfio-ap: fix memory leak in mdev remove callback Date: Fri, 21 May 2021 15:36:47 -0400 Message-Id: <20210521193648.940864-2-akrowiak@linux.ibm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210521193648.940864-1-akrowiak@linux.ibm.com> References: <20210521193648.940864-1-akrowiak@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: WLKCatEXMHZ6oeTGk5mM6n4YN6M11OeS X-Proofpoint-ORIG-GUID: 3D3viOYNtGAtkJhbKBR6FBY81fx9SAKX X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-05-21_08:2021-05-20,2021-05-21 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 adultscore=0 mlxlogscore=999 bulkscore=0 priorityscore=1501 phishscore=0 impostorscore=0 malwarescore=0 mlxscore=0 suspectscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105210103 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org 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 Reviewed-by: Cornelia Huck --- 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); -- 2.30.2