Subject: Re: [PATCH v2 -net-2.6] ll_temac: fix DMA resources leak

From: Kulikov Vasiliy <[email-masked]>
Date: Fri, 9 Jul 2010 21:59:52 +0400

On Fri, Jul 09, 2010 at 15:43 +0400, Kulikov Vasiliy wrote:
> On Thu, Jul 08, 2010 at 20:24 +0000, Denis Kirjanov wrote:
> > V2: Check pointers before releasing resources.
> > 
> > Fix DMA resources leak.
> > Signed-off-by: Denis Kirjanov <[email-masked]>
> > Signed-off-by: Kulikov Vasiliy <[email-masked]>
> > ---
> >  1 files changed, 32 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/net/ll_temac_main.c b/drivers/net/ll_temac_main.c
> > index fa303c8..b57d0ff 100644
> > --- a/drivers/net/ll_temac_main.c
> > +++ b/drivers/net/ll_temac_main.c
> > @@ -193,6 +193,35 @@ static int temac_dcr_setup(struct temac_local *lp, struct of_device *op,
> >  #endif
> >  
> >  /**
> > + *  * temac_dma_bd_release - Release buffer descriptor rings
> > + */
> > +static void temac_dma_bd_release(struct net_device *ndev)
> > +{
> > +	struct temac_local *lp = netdev_priv(ndev);
> > +	int i;
> > +
> > +	for (i = 0; i < RX_BD_NUM; i++) {
> > +		if (!lp->rx_skb[i])
> > +			break;
> > +		else {
> > +			dma_unmap_single(ndev->dev.parent, lp->rx_bd_v[i].phys,
> > +					XTE_MAX_JUMBO_FRAME_SIZE, DMA_FROM_DEVICE);
> > +			dev_kfree_skb(lp->rx_skb[i]);
> > +		}
> > +	}
> This cycle is needed only if (lp->rx_skb != NULL).
> 
> > +	if (lp->rx_bd_v)
> > +		dma_free_coherent(ndev->dev.parent,
> > +				sizeof(*lp->rx_bd_v) * RX_BD_NUM,
> > +				lp->rx_bd_v, lp->rx_bd_p);
> > +	if (lp->tx_bd_v)
> > +		dma_free_coherent(ndev->dev.parent,
> > +				sizeof(*lp->tx_bd_v) * TX_BD_NUM,
> > +				lp->tx_bd_v, lp->tx_bd_p);
> After temac_dma_bd_release() lp->rx_bd_v and lp->rx_bd_p are freed but
> are nonzero. If lp->rx_skb allocation fails second time then these DMA's
> would be freed second time.
> lp->tx_bd_v = lp->rx_bd_v = NULL here fixes this.
> 
> > +	if (lp->rx_skb)
> > +		kfree(lp->rx_skb);
> > +}
> > +
> > +/**
> >   * temac_dma_bd_init - Setup buffer descriptor rings
> >   */
> >  static int temac_dma_bd_init(struct net_device *ndev)
> > @@ -275,6 +304,7 @@ static int temac_dma_bd_init(struct net_device *ndev)
> >  	return 0;
> >  
> >  out:
> > +	temac_dma_bd_release(ndev);
> >  	return -ENOMEM;
> >  }
> >  
> > @@ -858,6 +888,8 @@ static int temac_stop(struct net_device *ndev)
> >  		phy_disconnect(lp->phy_dev);
> >  	lp->phy_dev = NULL;
> >  
> > +	temac_dma_bd_release(ndev);
> > +
> >  	return 0;
> >  }
> >  
I've fixed it in PATCH v3.

http://marc.info/?l=kernel-janitors&m=127869815002994&w=2