From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH v8 2/3] tcm_vhost: Add hotplug/hotunplug support
Date: Wed, 24 Apr 2013 13:51:19 +0300
Message-ID: <20130424105119.GA12865@redhat.com>
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	<20130424091833.GB11245@redhat.com>
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To: Asias He <asias@redhat.com>
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, target-devel@vger.kernel.org, Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
List-Id: virtualization@lists.linuxfoundation.org

On Wed, Apr 24, 2013 at 06:06:25PM +0800, Asias He wrote:
> > > +{
> > > +
> > > +	struct vhost_scsi *vs = tpg->vhost_scsi;
> > > +	struct vhost_virtqueue *vq;
> > > +	u32 reason;
> > > +	int ret;
> > > +
> > > +	mutex_lock(&tpg->tv_tpg_mutex);
> > > +	vs = tpg->vhost_scsi;
> > > +	mutex_unlock(&tpg->tv_tpg_mutex);
> > > +	if (!vs)
> > > +		return -ENODEV;
> > > +
> > 
> > What if clear_endpoint and close happen at this
> > point? Can vhost_scsi go away so tcm_vhost_check_feature
> > references freed memory?
> 
> There is no easy way to handle this.

Take a reference somewhere so this can't happen?