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Subject: Re: [PATCH 2/8] vfio/mdev: Avoid release parent reference during
 error path
To:     Parav Pandit <parav@mellanox.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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References: <1553296835-37522-1-git-send-email-parav@mellanox.com>
 <1553296835-37522-3-git-send-email-parav@mellanox.com>
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From:   Kirti Wankhede <kwankhede@nvidia.com>
Message-ID: <7c51995d-a318-62bf-dbb3-34ed8296fd82@nvidia.com>
Date:   Mon, 25 Mar 2019 23:57:01 +0530
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On 3/23/2019 4:50 AM, Parav Pandit wrote:
> During mdev parent registration in mdev_register_device(),
> if parent device is duplicate, it releases the reference of existing
> parent device.
> This is incorrect. Existing parent device should not be touched.
> 
> Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
> Signed-off-by: Parav Pandit <parav@mellanox.com>
> ---
>  drivers/vfio/mdev/mdev_core.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index 3e5880a..4f213e4d 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -182,6 +182,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
>  	/* Check for duplicate */
>  	parent = __find_parent_device(dev);
>  	if (parent) {
> +		parent = NULL;
>  		ret = -EEXIST;
>  		goto add_dev_err;
>  	}
> 

Agreed. Thanks for fixing this.

Reviewed By: Kirti Wankhede <kwankhede@nvidia.com>

Thanks,
Kirti