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Date:   Fri, 13 Dec 2019 12:13:22 +0100
From:   Steffen Klassert <steffen.klassert@secunet.com>
To:     Florian Westphal <fw@strlen.de>
CC:     Josh Hunt <johunt@akamai.com>, <herbert@gondor.apana.org.au>,
        David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>
Subject: Re: crash in __xfrm_state_lookup on 4.19 LTS
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On Fri, Dec 13, 2019 at 11:25:12AM +0100, Florian Westphal wrote:
> Steffen Klassert <steffen.klassert@secunet.com> wrote:
> > 
> > We destroy the states with a workqueue by doing schedule_work().
> > I think we should better use call_rcu to make sure that a
> > rcu grace period has elapsed before the states are destroyed.
> 
> xfrm_state_gc_task calls synchronize_rcu after stealing the gc list and
> before destroying those states, so I don't think this is a problem.

That's true, I've missed this. In that case, I don't
have an idea what is the root cause of these crashes.
We need to find a way to reproduce it.