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Date:   Thu, 1 Apr 2021 11:12:43 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Doug Ledford <dledford@redhat.com>,
        Mark Zhang <markzhang@nvidia.com>, linux-rdma@vger.kernel.org
Subject: Re: [PATCH rdma-next 3/6] IB/cm: Remove "mad_agent" parameter of
 ib_modify_mad
Message-ID: <YGWAexN7nZx5ac9J@unreal>
References: <20210318100309.670344-1-leon@kernel.org>
 <20210318100309.670344-4-leon@kernel.org>
 <20210329124101.GA887238@nvidia.com>
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On Mon, Mar 29, 2021 at 09:41:01AM -0300, Jason Gunthorpe wrote:
> On Thu, Mar 18, 2021 at 12:03:06PM +0200, Leon Romanovsky wrote:
> 
> > +static void cm_send_free_msg(struct ib_mad_send_buf *msg)
> > +{
> > +	struct cm_id_private *cm_id_priv;
> > +
> > +	cm_id_priv = msg->context[0];
> > +	if (!cm_id_priv || cm_id_priv->msg != msg) {
> > +		cm_free_msg(msg);
> > +		return;
> > +	}
> > +
> > +	spin_lock_irq(&cm_id_priv->lock);
> > +	cm_free_msg(msg);
> > +	cm_id_priv->msg = NULL;
> > +	spin_unlock_irq(&cm_id_priv->lock);
> > +}
> 
> Either the whole sequence should be inside the lock or nothing should
> be in the lock..

I see the race now, thanks for pointing it.

> 
> Oh this is all messed up and needs a big fix. Review and include this
> in the series and drop the above function.
> 
> https://github.com/jgunthorpe/linux/commits/for-markz

We will take a look on it.

Thanks

> 
> Jason