linux-kernel - Re: [PATCH 1/5] hisi_acc_vfio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ad6cd915-89c4-299e-03d2-8caab500809a@huawei.com>
Date:   Wed, 21 Sep 2022 11:13:26 +0800
From:   liulongfang <liulongfang@...wei.com>
To:     Shameerali Kolothum Thodi <shameerali.kolothum.thodi@...wei.com>,
        "Jason Gunthorpe" <jgg@...dia.com>,
        Alex Williamson <alex.williamson@...hat.com>
CC:     "cohuck@...hat.com" <cohuck@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxarm@...neuler.org" <linuxarm@...neuler.org>
Subject: Re: [PATCH 1/5] hisi_acc_vfio_pci: Fixes a memory leak bug

On 2022/9/21 1:03, Shameerali Kolothum Thodi wrote:
> 
> 
>> -----Original Message-----
>> From: Jason Gunthorpe [mailto:jgg@...dia.com]
>> Sent: 20 September 2022 17:38
>> To: Alex Williamson <alex.williamson@...hat.com>
>> Cc: liulongfang <liulongfang@...wei.com>; Shameerali Kolothum Thodi
>> <shameerali.kolothum.thodi@...wei.com>; cohuck@...hat.com;
>> linux-kernel@...r.kernel.org; linuxarm@...neuler.org
>> Subject: Re: [PATCH 1/5] hisi_acc_vfio_pci: Fixes a memory leak bug
>>
>> On Tue, Sep 20, 2022 at 10:34:43AM -0600, Alex Williamson wrote:
>>> On Thu, 15 Sep 2022 09:31:53 +0800
>>> Longfang Liu <liulongfang@...wei.com> wrote:
>>>
>>>> During the stop copy phase of live migration, the driver allocates a
>>>> memory for the migrated data to save the data.
>>>>
>>>> When an exception occurs when the driver reads device data, the
>>>> driver will report an error to qemu and exit the current migration state.
>>>> But this memory is not released, which will lead to a memory leak
>>>> problem.
>>
>> Why isn't it released? The fput() releases it:
>>
>> static int hisi_acc_vf_release_file(struct inode *inode, struct file *filp) {
>> 	struct hisi_acc_vf_migration_file *migf = filp->private_data;
>>
>> 	hisi_acc_vf_disable_fd(migf);
>> 	mutex_destroy(&migf->lock);
>> 	kfree(migf);
>>         ^^^^^^^^^^
>>
>> This patch looks wrong to me.
> 
> That's right. Missed that. Sorry of the oversight.
> 
Yes, fput will call release in ops of file, here will call hisi_acc_vf_release_file
to complete the release operation of migf, so this patch is unnecessary.

But there is another place that needs to be modified:
hisi_acc_vf_disable_fd in hisi_acc_vf_disable_fds is not needed,
because it will have an fput next. Is this correct?

> Thanks,
> Shameer
> 
> .
Thanks,
Longfang.
>