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Subject: Re: [PATCH v3] net: xfrm: Add '_rcu' tag for rcu protected pointer in
 netns_xfrm
To:     Steffen Klassert <steffen.klassert@secunet.com>,
        Eric Dumazet <eric.dumazet@gmail.com>
Cc:     Su Yanjun <suyj.fnst@cn.fujitsu.com>, davem@davemloft.net,
        fw@strlen.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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 <b2beff03-f789-5c8b-bd69-57ece92372f8@gmail.com>
 <20190319151503.GW6035@gauss3.secunet.de>
From:   Eric Dumazet <eric.dumazet@gmail.com>
Message-ID: <fc5b9608-4980-ae05-fab5-d050b80cf49e@gmail.com>
Date:   Tue, 19 Mar 2019 08:52:46 -0700
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On 03/19/2019 08:15 AM, Steffen Klassert wrote:
> On Mon, Mar 18, 2019 at 10:22:46AM -0700, Eric Dumazet wrote:
>>
>>
>> On 03/11/2019 03:10 AM, Steffen Klassert wrote:
>>> On Wed, Mar 06, 2019 at 08:54:08PM -0500, Su Yanjun wrote:
>>>> For rcu protected pointers, we'd better add '__rcu' for them.
>>>>
>>>> Once added '__rcu' tag for rcu protected pointer, the sparse tool reports
>>>> warnings.
>>>>
>>>> net/xfrm/xfrm_user.c:1198:39: sparse:    expected struct sock *sk
>>>> net/xfrm/xfrm_user.c:1198:39: sparse:    got struct sock [noderef] <asn:4> *nlsk
>>>> [...]
>>>>
>>>> So introduce a new wrapper function of nlmsg_unicast  to handle type
>>>> conversions.
>>>>
>>>> This patch also fixes a direct access of a rcu protected socket.
>>>>
>>>> Fixes: be33690d8fcf("[XFRM]: Fix aevent related crash")
>>>> Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com>
>>>
>>> Patch applied, thanks!
>>>
>>
>> Has this patch ever been tested ?
> 
> I had this on your testing system and it did
> not complain. But maybe my testcases did not
> trigger that codepath. Su, can you answer
> on Eric question?
> 

I can release four syzbot reports if you want.