netdev - Re: [PATCH net] macvlan: add cond_resched() during multicast processing

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Date:   Mon, 9 Mar 2020 18:09:18 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Mahesh Bandewar <maheshb@...gle.com>,
        David Miller <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>
Cc:     Eric Dumazet <edumazet@...gle.com>,
        Mahesh Bandewar <mahesh@...dewar.net>
Subject: Re: [PATCH net] macvlan: add cond_resched() during multicast
 processing



On 3/9/20 3:57 PM, Mahesh Bandewar wrote:
> The Rx bound multicast packets are deferred to a workqueue and
> macvlan can also suffer from the same attack that was discovered
> by Syzbot for IPvlan. This solution is not as effective as in
> IPvlan. IPvlan defers all (Tx and Rx) multicast packet processing
> to a workqueue while macvlan does this way only for the Rx. This
> fix should address the Rx codition to certain extent.

condition

> 
> Tx is still suseptible.

susceptible ? Not sure what you want to say here.

 Tx multicast processing happens when
> .ndo_start_xmit is called, hence we cannot add cond_resched().
> However, it's not that severe since the user which is generating
>  / flooding will be affected the most.
> 
> Fixes: 412ca1550cbe ("macvlan: Move broadcasts into a work queue")
> Signed-off-by: Mahesh Bandewar <maheshb@...gle.com>
> 



Reviewed-by: Eric Dumazet <edumazet@...gle.com>