ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN (da8ded40) · Commits · 戴 / test

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>

fs/ocfs2/cluster/tcp.c

+17 −5

Original line number	Diff line number	Diff line
		@@ -1964,17 +1964,29 @@ 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);
		if (ready != NULL)
		ready(sk, bytes);
		}

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