Subject: + ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen.patch added to -mm tree
To: tariq.x.saeed@xxxxxxxxxx,jlbec@xxxxxxxxxxxx,mfasheh@xxxxxxxx,srinivas.eeda@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 20 Dec 2013 15:30:15 -0800
The patch titled
Subject: ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN
has been added to the -mm tree. Its filename is
ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen.patch
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------------------------------------------------------
From: Tariq Saeed <tariq.x.saeed@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Signed-off-by: Srinivas Eeda <srinivas.eeda@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Mark Fasheh <mfasheh@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/cluster/tcp.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff -puN fs/ocfs2/cluster/tcp.c~ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen fs/ocfs2/cluster/tcp.c
--- a/fs/ocfs2/cluster/tcp.c~ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen
+++ a/fs/ocfs2/cluster/tcp.c
@@ -1973,18 +1973,30 @@ static void o2net_listen_data_ready(stru
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)
_
Patches currently in -mm which might be from tariq.x.saeed@xxxxxxxxxx are
ocfs2-o2net-incorrect-to-terminate-accepting-connections-loop-upon-rejecting-an-invalid-one.patch
ocfs2-punch-hole-should-return-einval-if-the-length-argument-in-ioctl-is-negative.patch
ocfs2-o2net-o2net_listen_data_ready-should-do-nothing-if-socket-state-is-not-tcp_listen.patch
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