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From: Al Viro <viro@zeniv.linux.org.uk>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Eric Biggers <ebiggers@kernel.org>,
	netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, Mao Wenan <maowenan@huawei.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Lorenzo Colitti <lorenzo@google.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: [PATCH net] net: socket: set sock->sk to NULL after calling proto_ops::release()
Date: Fri, 22 Feb 2019 19:08:50 +0000	[thread overview]
Message-ID: <20190222190850.GF2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <0de89a50-6d5c-1d7b-19f5-9a13465bcebd@gmail.com>

On Fri, Feb 22, 2019 at 10:25:09AM -0800, Eric Dumazet wrote:
> 
> 
> On 02/22/2019 09:57 AM, Eric Biggers wrote:
> 
> > ->setattr() is called under inode_lock(), which __sock_release() also takes.  So
> > the uses of sock->sk are serialized.  See commit 6d8c50dcb029 ("socket: close
> > race condition between sock_close() and sockfs_setattr()").
> 
> Oh right, we added another inode_lock()/inode_unlock() for sock_close()

An interesting question is whether anything else will be confused by
	sock->sk && sock->sk->sk_socket != sock

I'd still like to figure out if we could simply make sock_orphan()
do something like
	if (likely(sk->sk_socket))
		sk->sk_socket->sk = NULL;
just before sk_set_socket(sk, NULL);

That would make for much easier rules; the question is whether anything
relies upon the windows when linkage between socket and sock is not
symmetrical...

  reply	other threads:[~2019-02-22 19:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-21 22:13 [PATCH net] net: socket: set sock->sk to NULL after calling proto_ops::release() Eric Biggers
2019-02-22  2:51 ` Al Viro
2019-02-22 17:45 ` Eric Dumazet
2019-02-22 17:57   ` Eric Biggers
2019-02-22 18:25     ` Eric Dumazet
2019-02-22 19:08       ` Al Viro [this message]
2019-02-22 18:05 ` Cong Wang
2019-02-25 18:41 ` David Miller

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