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From:   Haiyang Zhang <haiyangz@microsoft.com>
To:     Wenwen Wang <wenwen@cs.uga.edu>
CC:     KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Sasha Levin <sashal@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        "open list:Hyper-V CORE AND DRIVERS" <linux-hyperv@vger.kernel.org>,
        "open list:NETWORKING DRIVERS" <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] hv_netvsc: Fix a memory leak bug
Thread-Topic: [PATCH] hv_netvsc: Fix a memory leak bug
Thread-Index: AQHVUt0lIPzKhtX2+0Owd7O+SbqtXqb7F/Ag
Date:   Wed, 14 Aug 2019 20:35:17 +0000
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References: <1565813771-8967-1-git-send-email-wenwen@cs.uga.edu>
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> -----Original Message-----
> From: Wenwen Wang <wenwen@cs.uga.edu>
> Sent: Wednesday, August 14, 2019 4:16 PM
> To: Wenwen Wang <wenwen@cs.uga.edu>
> Cc: KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger
> <sthemmin@microsoft.com>; Sasha Levin <sashal@kernel.org>; David S.
> Miller <davem@davemloft.net>; open list:Hyper-V CORE AND DRIVERS
> <linux-hyperv@vger.kernel.org>; open list:NETWORKING DRIVERS
> <netdev@vger.kernel.org>; open list <linux-kernel@vger.kernel.org>
> Subject: [PATCH] hv_netvsc: Fix a memory leak bug
>=20
> In rndis_filter_device_add(), 'rndis_device' is allocated through kzalloc=
()
> by invoking get_rndis_device(). In the following execution, if an error
> occurs, the execution will go to the 'err_dev_remv' label. However, the
> allocated 'rndis_device' is not deallocated, leading to a memory leak bug=
.
>=20
> Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
> ---
>  drivers/net/hyperv/rndis_filter.c | 1 +
>  1 file changed, 1 insertion(+)
>=20
> diff --git a/drivers/net/hyperv/rndis_filter.c
> b/drivers/net/hyperv/rndis_filter.c
> index 317dbe9..ed35085 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -1420,6 +1420,7 @@ struct netvsc_device
> *rndis_filter_device_add(struct hv_device *dev,
>=20
>  err_dev_remv:
>  	rndis_filter_device_remove(dev, net_device);
> +	kfree(rndis_device);

The kfree() is not necessary here.=20
Because it is already freed by --
rndis_filter_device_remove() --> netvsc_device_remove()=20
--> free_netvsc_device_rcu() --> free_netvsc_device()
--> kfree(nvdev->extension);  //This frees rndis_device.

Thanks,
- Haiyang