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

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Message-ID: <b7fc8184-8a51-9c7e-6ef5-aa245edb7b9d@linux.ibm.com>
Date:   Thu, 13 May 2021 10:19:49 -0400
From:   Tony Krowiak <akrowiak@...ux.ibm.com>
To:     Christian Borntraeger <borntraeger@...ibm.com>,
        Jason Gunthorpe <jgg@...dia.com>
Cc:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        cohuck@...hat.com, pasic@...ux.vnet.ibm.com, jjherne@...ux.ibm.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 5/12/21 11:32 AM, Christian Borntraeger wrote:
>
>
> On 12.05.21 14:41, Jason Gunthorpe wrote:
>> On Mon, May 10, 2021 at 05:48:37PM -0400, 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@...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(-)
>>
>> Can you please ensure this goes to a -rc branch or through Alex's
>> tree?
>
> So you want this is 5.13-rc?
> I can apply this to the s390 tree if that is ok.

If it is in time for 5.13.-rc, then yes, go ahead and
apply it.