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ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN
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>
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1 changed files with 17 additions and 5 deletions
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@ -1964,17 +1964,29 @@ static void o2net_listen_data_ready(struct sock *sk, int bytes)
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goto out;
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}
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/* ->sk_data_ready is also called for a newly established child socket
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* before it has been accepted and the acceptor has set up their
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* data_ready.. we only want to queue listen work for our listening
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* socket */
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/* This callback may called twice when a new connection
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* is being established as a child socket inherits everything
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* from a parent LISTEN socket, including the data_ready cb of
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* the parent. This leads to a hazard. In o2net_accept_one()
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* we are still initializing the child socket but have not
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* changed the inherited data_ready callback yet when
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* data starts arriving.
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* We avoid this hazard by checking the state.
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* For the listening socket, the state will be TCP_LISTEN; for the new
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* socket, will be TCP_ESTABLISHED. Also, in this case,
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* sk->sk_user_data is not a valid function pointer.
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*/
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if (sk->sk_state == TCP_LISTEN) {
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mlog(ML_TCP, "bytes: %d\n", bytes);
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queue_work(o2net_wq, &o2net_listen_work);
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} else {
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ready = NULL;
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}
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out:
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read_unlock(&sk->sk_callback_lock);
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if (ready != NULL)
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ready(sk, bytes);
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}
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