linux-kernel - Re: [PATCH] virtio-pci: fix memory leak of vp

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Message-ID: <9589357f-8d23-5a48-c5f6-ba17eb79cf57@linux.alibaba.com>
Date:   Fri, 7 Jan 2022 10:36:48 +0800
From:   Xianting Tian <xianting.tian@...ux.alibaba.com>
To:     Jason Wang <jasowang@...hat.com>
Cc:     mst <mst@...hat.com>,
        virtualization <virtualization@...ts.linux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] virtio-pci: fix memory leak of vp_dev

Thanks, I checked this before your reply, it is not a bug,

Sorry for the inconvenience caused.

在 2022/1/7 上午10:34, Jason Wang 写道:
> On Thu, Jan 6, 2022 at 4:31 PM Xianting Tian
> <xianting.tian@...ux.alibaba.com> wrote:
>> In virtio_pci_probe(), vp_dev will not be freed if it goes to
>> "err_register" branch. fix it
>>
>> Signed-off-by: Xianting Tian <xianting.tian@...ux.alibaba.com>
> So we had this:
>
> commit 33635bd976fb4c3ccf0cfbb81a8d29bb87760607
> Author: weiping zhang <zhangweiping@...ichuxing.com>
> Date:   Thu Dec 21 20:40:24 2017 +0800
>
>      virtio_pci: don't kfree device on register failure
>
>      As mentioned at drivers/base/core.c:
>      /*
>       * NOTE: _Never_ directly free @dev after calling this function, even
>       * if it returned an error! Always use put_device() to give up the
>       * reference initialized in this function instead.
>       */
>      so we don't free vp_dev until vp_dev->vdev.dev.release be called.
>
>      Signed-off-by: weiping zhang <zhangweiping@...ichuxing.com>
>      Reviewed-by: Cornelia Huck <cohuck@...hat.com>
>      Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
>
> Any reason that the above fix is wrong?
>
> Thanks
>
>> ---
>>   drivers/virtio/virtio_pci_common.c | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
>> index fdbde1db5..48b5ac15e 100644
>> --- a/drivers/virtio/virtio_pci_common.c
>> +++ b/drivers/virtio/virtio_pci_common.c
>> @@ -602,8 +602,7 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
>>   err_enable_device:
>>          if (reg_dev)
>>                  put_device(&vp_dev->vdev.dev);
>> -       else
>> -               kfree(vp_dev);
>> +       kfree(vp_dev);
>>          return rc;
>>   }
>>
>> --
>> 2.17.1
>>