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Date:   Tue, 8 Oct 2019 08:04:14 +0200
From:   Florian Westphal <fw@strlen.de>
To:     Maciej =?utf-8?Q?=C5=BBenczykowski?= <zenczykowski@gmail.com>
Cc:     Maciej =?utf-8?Q?=C5=BBenczykowski?= <maze@google.com>,
        "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Eric Dumazet <edumazet@google.com>,
        Pablo Neira Ayuso <pablo@netfilter.org>
Subject: Re: [PATCH 2/2] netfilter: revert "conntrack: silent a memory leak
 warning"
Message-ID: <20191008060414.GB25052@breakpoint.cc>
References: <20191008053507.252202-1-zenczykowski@gmail.com>
 <20191008053507.252202-2-zenczykowski@gmail.com>
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Maciej Żenczykowski <zenczykowski@gmail.com> wrote:
> From: Maciej Żenczykowski <maze@google.com>
> 
> This reverts commit 114aa35d06d4920c537b72f9fa935de5dd205260.
> 
> By my understanding of kmemleak the reasoning for this patch
> is incorrect.  If kmemleak couldn't handle rcu we'd have it
> reporting leaks all over the place.  My belief is that this
> was instead papering over a real leak.

Perhaps, but note that this is related to nfct->ext, not nfct itself.

I think we could remove __krealloc and use krealloc directly with
a bit of changes in the nf_conntrack core to make sure we do not
access nfct->ext without holding a reference to nfct, and then drop
rcu protection of nfct->ext, I don't think its strictly required anymore.