linux-kernel - Re: [RFC PATCH 02/24] vhost-vdpa: fix vqs leak in vhost_vdpa

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Date:   Thu, 24 Sep 2020 10:48:16 +0300
From:   Eli Cohen <elic@...dia.com>
To:     Jason Wang <jasowang@...hat.com>
CC:     <mst@...hat.com>, <lulu@...hat.com>, <kvm@...r.kernel.org>,
        <virtualization@...ts.linux-foundation.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <rob.miller@...adcom.com>, <lingshan.zhu@...el.com>,
        <eperezma@...hat.com>, <hanand@...inx.com>,
        <mhabets@...arflare.com>, <eli@...lanox.com>,
        <amorenoz@...hat.com>, <maxime.coquelin@...hat.com>,
        <stefanha@...hat.com>, <sgarzare@...hat.com>
Subject: Re: [RFC PATCH 02/24] vhost-vdpa: fix vqs leak in vhost_vdpa_open()

On Thu, Sep 24, 2020 at 11:21:03AM +0800, Jason Wang wrote:
> We need to free vqs during the err path after it has been allocated
> since vhost won't do that for us.
> 
> Signed-off-by: Jason Wang <jasowang@...hat.com>
> ---
>  drivers/vhost/vdpa.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 796fe979f997..9c641274b9f3 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -764,6 +764,12 @@ static void vhost_vdpa_free_domain(struct vhost_vdpa *v)
>  	v->domain = NULL;
>  }
>  
> +static void vhost_vdpa_cleanup(struct vhost_vdpa *v)
> +{
> +	vhost_dev_cleanup(&v->vdev);
> +	kfree(v->vdev.vqs);
> +}
> +

Wouldn't it be cleaner to call kfree(vqs) explicilty inside
vhost_vdpa_open() in case of failure and keep the symetry of
vhost_dev_init()/vhost_dev_cleanup()?

>  static int vhost_vdpa_open(struct inode *inode, struct file *filep)
>  {
>  	struct vhost_vdpa *v;
> @@ -809,7 +815,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
>  	return 0;
>  
>  err_init_iotlb:
> -	vhost_dev_cleanup(&v->vdev);
> +	vhost_vdpa_cleanup(v);
>  err:
>  	atomic_dec(&v->opened);
>  	return r;
> @@ -840,8 +846,7 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep)
>  	vhost_vdpa_free_domain(v);
>  	vhost_vdpa_config_put(v);
>  	vhost_vdpa_clean_irq(v);
> -	vhost_dev_cleanup(&v->vdev);
> -	kfree(v->vdev.vqs);
> +	vhost_vdpa_cleanup(v);
>  	mutex_unlock(&d->mutex);
>  
>  	atomic_dec(&v->opened);
> -- 
> 2.20.1
>