netdev - Re: [PATCH net] bonding: Fix bonding crash

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Date:   Sun, 04 Sep 2016 11:41:28 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     mahesh@...dewar.net
Cc:     j.vosburgh@...il.com, gospo@...ulusnetworks.com, vfalico@...il.com,
        maheshb@...gle.com, edumazet@...gle.com, netdev@...r.kernel.org
Subject: Re: [PATCH net] bonding: Fix bonding crash

From: Mahesh Bandewar <mahesh@...dewar.net>
Date: Thu,  1 Sep 2016 22:18:34 -0700

> From: Mahesh Bandewar <maheshb@...gle.com>
> 
> Following few steps will crash kernel -
> 
>   (a) Create bonding master
>       > modprobe bonding miimon=50
>   (b) Create macvlan bridge on eth2
>       > ip link add link eth2 dev mvl0 address aa:0:0:0:0:01 \
> 	   type macvlan
>   (c) Now try adding eth2 into the bond
>       > echo +eth2 > /sys/class/net/bond0/bonding/slaves
>       <crash>
> 
> Bonding does lots of things before checking if the device enslaved is
> busy or not.
> 
> In this case when the notifier call-chain sends notifications, the
> bond_netdev_event() assumes that the rx_handler /rx_handler_data is
> registered while the bond_enslave() hasn't progressed far enough to
> register rx_handler for the new slave.
> 
> This patch adds a rx_handler check that can be performed right at the
> beginning of the enslave code to avoid getting into this situation.
> 
> Signed-off-by: Mahesh Bandewar <maheshb@...gle.com>

Applied and queued up for -stable, thanks.