Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Message-ID: <01d3cd705b9ec9d5d6b286381951e6168269bda6.camel@redhat.com>
Subject: Re: [PATCH 2/8] vfio/mdev: Avoid release parent reference during
 error path
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Parav Pandit <parav@mellanox.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, kwankhede@nvidia.com,
        alex.williamson@redhat.com
Date:   Mon, 25 Mar 2019 13:49:36 +0200
In-Reply-To: <1553296835-37522-3-git-send-email-parav@mellanox.com>
References: <1553296835-37522-1-git-send-email-parav@mellanox.com>
         <1553296835-37522-3-git-send-email-parav@mellanox.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, 2019-03-22 at 18:20 -0500, 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;
>  	}

This is also clearly an issue.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky