RE: [Xen-devel] [xen-unstable test] 1959: FAIL [and 1 more messages]

[Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>]

On Wed, 2010-08-11 at 04:19 +0100, Xu, Dongxiao wrote:
> From 791fc8ed6e2888af3bd398f22562776c757cc4ac Mon Sep 17 00:00:00 2001
> From: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
> Date: Wed, 11 Aug 2010 11:06:06 +0800
> Subject: [PATCH] Netfront: Fix save/restore after enabled smart poll
> feature
> 
> When s/r the guest, the shared ring will be set to NULL, and
> in this case the polling timer interrupt should stop.
> 
> This fix includes the two parts:
> 1) Stop hrtimer when guest suspends.
> 2) Add check to avoid NULL pointer dereference.

Looks good to me but do you really need 2) given 1)?

Ian.


> 
> Thanks Ian J for reporting the problem.
> 
> Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
> ---
>  drivers/net/xen-netfront.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
> index 328fe40..eaea132 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -1289,6 +1289,14 @@ static void xennet_disconnect_backend(struct
> netfront_info *info)
>         info->rx.sring = NULL;
>  }
>  
> +static int netfront_suspend(struct xenbus_device *dev, pm_message_t
> state)
> +{
> +       struct netfront_info *info = dev_get_drvdata(&dev->dev);
> +       struct hrtimer *timer = &info->smart_poll.timer;
> +       hrtimer_cancel(timer);
> +       return 0;
> +}
> +
>  /**
>   * We are reconnecting to the backend, due to a suspend/resume, or a
> backend
>   * driver restart.  We tear down our netif structure and recreate it,
> but
> @@ -1340,6 +1348,10 @@ static enum hrtimer_restart
> smart_poll_function(struct hrtimer *timer)
>         np = netdev_priv(dev);
>  
>         spin_lock_irqsave(&np->tx_lock, flags);
> +
> +       if (!np->rx.sring)
> +               goto end;
> +
>         np->smart_poll.counter++;
>  
>         if (likely(netif_carrier_ok(dev))) {
> @@ -1910,6 +1922,7 @@ static struct xenbus_driver netfront_driver = {
>         .ids = netfront_ids,
>         .probe = netfront_probe,
>         .remove = __devexit_p(xennet_remove),
> +       .suspend = netfront_suspend,
>         .resume = netfront_resume,
>         .otherend_changed = netback_changed,
>  }; 


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