netdev - Re: [PATCH net v3] ovs: limit ovs recursions in ovs_execute

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Message-ID: <1452876357.1223.178.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Fri, 15 Jan 2016 08:45:57 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Hannes Frederic Sowa <hannes@...essinduktion.org>
Cc:	netdev@...r.kernel.org, dev@...nvswitch.org,
	Pravin Shelar <pshelar@....org>,
	Simon Horman <simon.horman@...ronome.com>
Subject: Re: [PATCH net v3] ovs: limit ovs recursions in ovs_execute_actions
 to not corrupt stack

On Fri, 2016-01-15 at 15:33 +0100, Hannes Frederic Sowa wrote:
> It was seen that defective configurations of openvswitch could overwrite
> the STACK_END_MAGIC and cause a hard crash of the kernel because of too
> many recursions within ovs.

...

> +
> +	preempt_disable();
> +	level = __this_cpu_inc_return(exec_actions_level);
> +	if (level > ovs_recursion_limit) {

if (unlikely(level > ovs_recursion_limit)) {