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ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN

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Orabug: 17330860

When accepting an incomming connection o2net_accept_one clones a child
data socket from the parent listening socket.  It then proceeds to setup
the child with callback o2net_data_ready() and sk_user_data to NULL.  If
data arrives in this window, o2net_listen_data_ready will be called with
some non-deterministic value in sk_user_data (not inherited).  We panic
when we page fault on sk_user_data -- in parent it is
sock_def_readable().

The fix is to recognize that this is a data socket being set up by
looking at the socket state and do nothing.

Signed-off-by: Tariq Saseed <tariq.x.saeed@oracle.com>
Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Tariq Saeed 2014-04-03 14:47:11 -07:00 committed by Linus Torvalds
parent db66c71577
commit da8ded405d
1 changed files with 17 additions and 5 deletions
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22
fs/ocfs2/cluster/tcp.c
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@ -1964,18 +1964,30 @@ static void o2net_listen_data_ready(struct sock *sk, int bytes)
goto out;
}
/* ->sk_data_ready is also called for a newly established child socket
* before it has been accepted and the acceptor has set up their
* data_ready.. we only want to queue listen work for our listening
* socket */
/* This callback may called twice when a new connection
* is being established as a child socket inherits everything
* from a parent LISTEN socket, including the data_ready cb of
* the parent. This leads to a hazard. In o2net_accept_one()
* we are still initializing the child socket but have not
* changed the inherited data_ready callback yet when
* data starts arriving.
* We avoid this hazard by checking the state.
* For the listening socket, the state will be TCP_LISTEN; for the new
* socket, will be TCP_ESTABLISHED. Also, in this case,
* sk->sk_user_data is not a valid function pointer.
*/
if (sk->sk_state == TCP_LISTEN) {
mlog(ML_TCP, "bytes: %d\n", bytes);
queue_work(o2net_wq, &o2net_listen_work);
} else {
ready = NULL;
}
out:
read_unlock(&sk->sk_callback_lock);
ready(sk, bytes);
if (ready != NULL)
ready(sk, bytes);
}
static int o2net_open_listening_sock(__be32 addr, __be16 port)