linux/net/rds/tcp_connect.c
Sowmini Varadhan aed20a53a7 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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-16 19:07:35 -07:00

190 lines
5.3 KiB
C

/*
* Copyright (c) 2006 Oracle. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/in.h>
#include <net/tcp.h>
#include "rds.h"
#include "tcp.h"
void rds_tcp_state_change(struct sock *sk)
{
void (*state_change)(struct sock *sk);
struct rds_conn_path *cp;
struct rds_tcp_connection *tc;
read_lock_bh(&sk->sk_callback_lock);
cp = sk->sk_user_data;
if (!cp) {
state_change = sk->sk_state_change;
goto out;
}
tc = cp->cp_transport_data;
state_change = tc->t_orig_state_change;
rdsdebug("sock %p state_change to %d\n", tc->t_sock, sk->sk_state);
switch (sk->sk_state) {
/* ignore connecting sockets as they make progress */
case TCP_SYN_SENT:
case TCP_SYN_RECV:
break;
case TCP_ESTABLISHED:
/* Force the peer to reconnect so that we have the
* TCP ports going from <smaller-ip>.<transient> to
* <larger-ip>.<RDS_TCP_PORT>. We avoid marking the
* RDS connection as RDS_CONN_UP until the reconnect,
* to avoid RDS datagram loss.
*/
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, false);
} else {
rds_connect_path_complete(cp, RDS_CONN_CONNECTING);
}
break;
case TCP_CLOSE_WAIT:
case TCP_CLOSE:
rds_conn_path_drop(cp, false);
default:
break;
}
out:
read_unlock_bh(&sk->sk_callback_lock);
state_change(sk);
}
int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
{
struct socket *sock = NULL;
struct sockaddr_in src, dest;
int ret;
struct rds_connection *conn = cp->cp_conn;
struct rds_tcp_connection *tc = cp->cp_transport_data;
/* for multipath rds,we only trigger the connection after
* the handshake probe has determined the number of paths.
*/
if (cp->cp_index > 0 && cp->cp_conn->c_npaths < 2)
return -EAGAIN;
mutex_lock(&tc->t_conn_path_lock);
if (rds_conn_path_up(cp)) {
mutex_unlock(&tc->t_conn_path_lock);
return 0;
}
ret = sock_create_kern(rds_conn_net(conn), PF_INET,
SOCK_STREAM, IPPROTO_TCP, &sock);
if (ret < 0)
goto out;
rds_tcp_tune(sock);
src.sin_family = AF_INET;
src.sin_addr.s_addr = (__force u32)conn->c_laddr;
src.sin_port = (__force u16)htons(0);
ret = sock->ops->bind(sock, (struct sockaddr *)&src, sizeof(src));
if (ret) {
rdsdebug("bind failed with %d at address %pI4\n",
ret, &conn->c_laddr);
goto out;
}
dest.sin_family = AF_INET;
dest.sin_addr.s_addr = (__force u32)conn->c_faddr;
dest.sin_port = (__force u16)htons(RDS_TCP_PORT);
/*
* once we call connect() we can start getting callbacks and they
* own the socket
*/
rds_tcp_set_callbacks(sock, cp);
ret = sock->ops->connect(sock, (struct sockaddr *)&dest, sizeof(dest),
O_NONBLOCK);
rdsdebug("connect to address %pI4 returned %d\n", &conn->c_faddr, ret);
if (ret == -EINPROGRESS)
ret = 0;
if (ret == 0) {
rds_tcp_keepalive(sock);
sock = NULL;
} else {
rds_tcp_restore_callbacks(sock, cp->cp_transport_data);
}
out:
mutex_unlock(&tc->t_conn_path_lock);
if (sock)
sock_release(sock);
return ret;
}
/*
* Before killing the tcp socket this needs to serialize with callbacks. The
* caller has already grabbed the sending sem so we're serialized with other
* senders.
*
* TCP calls the callbacks with the sock lock so we hold it while we reset the
* callbacks to those set by TCP. Our callbacks won't execute again once we
* hold the sock lock.
*/
void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
{
struct rds_tcp_connection *tc = cp->cp_transport_data;
struct socket *sock = tc->t_sock;
rdsdebug("shutting down conn %p tc %p sock %p\n",
cp->cp_conn, tc, sock);
if (sock) {
if (cp->cp_conn->c_destroy_in_prog)
rds_tcp_set_linger(sock);
sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
lock_sock(sock->sk);
rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
release_sock(sock->sk);
sock_release(sock);
}
if (tc->t_tinc) {
rds_inc_put(&tc->t_tinc->ti_inc);
tc->t_tinc = NULL;
}
tc->t_tinc_hdr_rem = sizeof(struct rds_header);
tc->t_tinc_data_rem = 0;
}