Re: [Intel-wired-lan] [PATCH 1/2] e1000e: Don't return uninitialized stats

From: "Neftin, Sasha" <sasha.neftin@intel•com>
To: "netdev@vger•kernel.org" <netdev@vger•kernel.org>
Cc: intel-wired-lan@lists•osuosl.org, "Ruinskiy,
	Dima" <dima.ruinskiy@intel•com>
Subject: Re: [Intel-wired-lan] [PATCH 1/2] e1000e: Don't return uninitialized stats
Date: Mon, 24 Apr 2017 11:17:39 +0300	[thread overview]
Message-ID: <caef8d69-9e47-bbcc-0758-e5900e1cb291@intel.com> (raw)
In-Reply-To: <630A6B92B7EDEB45A87E20D3D286660171182EED@hasmsx109.ger.corp.intel.com>

On 4/23/2017 15:53, Neftin, Sasha wrote:
> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@lists•osuosl.org] On Behalf Of Benjamin Poirier
> Sent: Saturday, April 22, 2017 00:20
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel•com>
> Cc: netdev@vger•kernel.org; intel-wired-lan@lists•osuosl.org; Stefan Priebe <s.priebe@profihost•ag>
> Subject: [Intel-wired-lan] [PATCH 1/2] e1000e: Don't return uninitialized stats
>
> Some statistics passed to ethtool are garbage because e1000e_get_stats64() doesn't write them, for example: tx_heartbeat_errors. This leaks kernel memory to userspace and confuses users.
>
> Do like ixgbe and use dev_get_stats() which first zeroes out rtnl_link_stats64.
>
> Reported-by: Stefan Priebe <s.priebe@profihost•ag>
> Signed-off-by: Benjamin Poirier <bpoirier@suse•com>
> ---
>   drivers/net/ethernet/intel/e1000e/ethtool.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/ethtool.c b/drivers/net/ethernet/intel/e1000e/ethtool.c
> index 7aff68a4a4df..f117b90cdc2f 100644
> --- a/drivers/net/ethernet/intel/e1000e/ethtool.c
> +++ b/drivers/net/ethernet/intel/e1000e/ethtool.c
> @@ -2063,7 +2063,7 @@ static void e1000_get_ethtool_stats(struct net_device *netdev,
>   
>   	pm_runtime_get_sync(netdev->dev.parent);
>   
> -	e1000e_get_stats64(netdev, &net_stats);
> +	dev_get_stats(netdev, &net_stats);
>   
>   	pm_runtime_put_sync(netdev->dev.parent);
>   
> --
> 2.12.2
>
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> Intel-wired-lan@lists•osuosl.org
> http://lists.osuosl.org/mailman/listinfo/intel-wired-lan

Hello,

We would like to not accept this patch. Suggested generic method 
'*dev_get_stats' (net/core/dev.c) calls 'ops->ndo_get_stats64' method 
which eventually calls e1000e_get_stats64 (netdev.c) - so there is same 
functionality. Also, see that 'e1000e_get_stats64' method in netdev.c 
(line 5928) calls 'memset' with 0's before update statistics.  Local 
sanity check in our lab shows 'tx_heartbeat_errors' counter reported as 0.

Thanks,

Sasha