From aed20a53a7d91e45c6a8cb8920c77aaaa88f76ee Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Sun, 16 Jul 2017 16:43:46 -0700 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- 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 @@ EXPORT_SYMBOL_GPL(rds_conn_path_drop); 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 @@ __rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...) 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 @@ out: "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; } -- 2.7.4