linux-kernel - Re: [PATCH] veth: Fix potential memory leak in veth

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Date:	Wed, 27 Apr 2016 12:57:14 +0200
From:	Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To:	Haishuang Yan <yanhaishuang@...s.chinamobile.com>,
	"David S. Miller" <davem@...emloft.net>,
	Toshiaki Makita <makita.toshiaki@....ntt.co.jp>
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] veth: Fix potential memory leak in veth_newlink

On 04/27/2016 12:42 PM, Haishuang Yan wrote:
> Free peer netdev when failed to configure peer link or register dev.
> 
> Signed-off-by: Haishuang Yan <yanhaishuang@...s.chinamobile.com>
> ---
>  drivers/net/veth.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/net/veth.c b/drivers/net/veth.c
> index f37a6e6..8bb9fb8 100644
> --- a/drivers/net/veth.c
> +++ b/drivers/net/veth.c
> @@ -472,7 +472,6 @@ err_register_dev:
>  	/* nothing to do */
>  err_configure_peer:
>  	unregister_netdevice(peer);
> -	return err;
>  
>  err_register_peer:
>  	free_netdev(peer);
> 

No, it won't leak. unregister_netdevice() will queue it on the todo list and at
the next rtnl unlock the peer device will get freed.
In fact calling it like this you'll hit BUG_ON(dev->reg_state != NETREG_UNREGISTERED) in
free_netdev so I guess you didn't even test your patch.