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Date: Sun, 16 Jul 2017 16:43:46 -0700
From: Sowmini Varadhan <sowmini.varadhan@...cle.com>
To: sowmini.varadhan@...cle.com
Cc: davem@...emloft.net, rds-devel@....oracle.com,
sowmini.varadhan@...cle.com, santosh.shilimkar@...cle.com
Subject: [PATCH net-next] rds: cancel send/recv work before queuing connection shutdown
We could end up executing rds_conn_shutdown before the rds_recv_worker
thread, then rds_conn_shutdown -> rds_tcp_conn_shutdown can do a
sock_release and set sock->sk to null, which may interleave in bad
ways with rds_recv_worker, e.g., it could result in:
"BUG: unable to handle kernel NULL pointer dereference at 0000000000000078"
[ffff881769f6fd70] release_sock at ffffffff815f337b
[ffff881769f6fd90] rds_tcp_recv at ffffffffa043c888 [rds_tcp]
[ffff881769f6fdb0] rds_recv_worker at ffffffffa04a4810 [rds]
[ffff881769f6fde0] process_one_work at ffffffff810a14c1
[ffff881769f6fe40] worker_thread at ffffffff810a1940
[ffff881769f6fec0] kthread at ffffffff810a6b1e
Also, do not enqueue any new shutdown workq items when the connection is
shutting down (this may happen for rds-tcp in softirq mode, if a FIN
or CLOSE is received while the modules is in the middle of an unload)
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
---
net/rds/connection.c | 16 ++++++++++------
net/rds/rds.h | 2 +-
net/rds/tcp.c | 2 +-
net/rds/tcp_connect.c | 4 ++--
net/rds/tcp_send.c | 2 +-
net/rds/threads.c | 2 +-
6 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/net/rds/connection.c b/net/rds/connection.c
index 50a3789..005bca6 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -374,13 +374,13 @@ static void rds_conn_path_destroy(struct rds_conn_path *cp)
if (!cp->cp_transport_data)
return;
- rds_conn_path_drop(cp);
- flush_work(&cp->cp_down_w);
-
/* make sure lingering queued work won't try to ref the conn */
cancel_delayed_work_sync(&cp->cp_send_w);
cancel_delayed_work_sync(&cp->cp_recv_w);
+ rds_conn_path_drop(cp, true);
+ flush_work(&cp->cp_down_w);
+
/* tear down queued messages */
list_for_each_entry_safe(rm, rtmp,
&cp->cp_send_queue,
@@ -664,9 +664,13 @@ void rds_conn_exit(void)
/*
* Force a disconnect
*/
-void rds_conn_path_drop(struct rds_conn_path *cp)
+void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
{
atomic_set(&cp->cp_state, RDS_CONN_ERROR);
+
+ if (!destroy && cp->cp_conn->c_destroy_in_prog)
+ return;
+
queue_work(rds_wq, &cp->cp_down_w);
}
EXPORT_SYMBOL_GPL(rds_conn_path_drop);
@@ -674,7 +678,7 @@ void rds_conn_path_drop(struct rds_conn_path *cp)
void rds_conn_drop(struct rds_connection *conn)
{
WARN_ON(conn->c_trans->t_mp_capable);
- rds_conn_path_drop(&conn->c_path[0]);
+ rds_conn_path_drop(&conn->c_path[0], false);
}
EXPORT_SYMBOL_GPL(rds_conn_drop);
@@ -706,5 +710,5 @@ void rds_conn_connect_if_down(struct rds_connection *conn)
vprintk(fmt, ap);
va_end(ap);
- rds_conn_path_drop(cp);
+ rds_conn_path_drop(cp, false);
}
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 516bcc8..3382695 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -700,7 +700,7 @@ struct rds_connection *rds_conn_create_outgoing(struct net *net,
void rds_conn_shutdown(struct rds_conn_path *cpath);
void rds_conn_destroy(struct rds_connection *conn);
void rds_conn_drop(struct rds_connection *conn);
-void rds_conn_path_drop(struct rds_conn_path *cpath);
+void rds_conn_path_drop(struct rds_conn_path *cpath, bool destroy);
void rds_conn_connect_if_down(struct rds_connection *conn);
void rds_conn_path_connect_if_down(struct rds_conn_path *cp);
void rds_for_each_conn_info(struct socket *sock, unsigned int len,
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index 431404d..6b7ee71 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -592,7 +592,7 @@ static void rds_tcp_sysctl_reset(struct net *net)
continue;
/* reconnect with new parameters */
- rds_conn_path_drop(tc->t_cpath);
+ rds_conn_path_drop(tc->t_cpath, false);
}
spin_unlock_irq(&rds_tcp_conn_lock);
}
diff --git a/net/rds/tcp_connect.c b/net/rds/tcp_connect.c
index cbe08a1..46f74da 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -69,14 +69,14 @@ void rds_tcp_state_change(struct sock *sk)
if (!IS_CANONICAL(cp->cp_conn->c_laddr, cp->cp_conn->c_faddr) &&
rds_conn_path_transition(cp, RDS_CONN_CONNECTING,
RDS_CONN_ERROR)) {
- rds_conn_path_drop(cp);
+ rds_conn_path_drop(cp, false);
} else {
rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
}
break;
case TCP_CLOSE_WAIT:
case TCP_CLOSE:
- rds_conn_path_drop(cp);
+ rds_conn_path_drop(cp, false);
default:
break;
}
diff --git a/net/rds/tcp_send.c b/net/rds/tcp_send.c
index 0d8616a..dc860d1 100644
--- a/net/rds/tcp_send.c
+++ b/net/rds/tcp_send.c
@@ -157,7 +157,7 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
"returned %d, "
"disconnecting and reconnecting\n",
&conn->c_faddr, cp->cp_index, ret);
- rds_conn_path_drop(cp);
+ rds_conn_path_drop(cp, false);
}
}
}
diff --git a/net/rds/threads.c b/net/rds/threads.c
index 2852bc1..f121daa 100644
--- a/net/rds/threads.c
+++ b/net/rds/threads.c
@@ -78,7 +78,7 @@ void rds_connect_path_complete(struct rds_conn_path *cp, int curr)
"current state is %d\n",
__func__,
atomic_read(&cp->cp_state));
- rds_conn_path_drop(cp);
+ rds_conn_path_drop(cp, false);
return;
}
--
1.7.1
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