From 46c28dbd4c23c3f7fa37f5ea48772af79c9cc40e Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Mon, 10 Apr 2017 14:58:01 +0200 Subject: [PATCH] net/smc: no socket state changes in tasklet context Several state changes occur during SMC socket closing. Currently state changes triggered locally occur in process context with lock_sock() taken while state changes triggered by peer occur in tasklet context with bh_lock_sock() taken. bh_lock_sock() does not wait till a lock_sock(() task in process context is finished. This may lead to races in socket state transitions resulting in dangling SMC-sockets, or it may lead to duplicate SMC socket freeing. This patch introduces a closing worker to run all state changes under lock_sock(). Signed-off-by: Ursula Braun Reviewed-by: Thomas Richter Reported-by: Dave Jones Signed-off-by: David S. Miller --- net/smc/af_smc.c | 8 ++++++-- net/smc/smc.h | 1 + net/smc/smc_cdc.c | 9 +++++++-- net/smc/smc_close.c | 39 +++++++++++++++++++++++++-------------- net/smc/smc_close.h | 2 +- net/smc/smc_core.c | 2 +- 6 files changed, 41 insertions(+), 20 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 093803786eac..3b7eda6c27de 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -451,6 +451,9 @@ static int smc_connect_rdma(struct smc_sock *smc) goto decline_rdma_unlock; } + smc_close_init(smc); + smc_rx_init(smc); + if (local_contact == SMC_FIRST_CONTACT) { rc = smc_ib_ready_link(link); if (rc) { @@ -477,7 +480,6 @@ static int smc_connect_rdma(struct smc_sock *smc) mutex_unlock(&smc_create_lgr_pending); smc_tx_init(smc); - smc_rx_init(smc); out_connected: smc_copy_sock_settings_to_clc(smc); @@ -800,6 +802,9 @@ static void smc_listen_work(struct work_struct *work) goto decline_rdma; } + smc_close_init(new_smc); + smc_rx_init(new_smc); + rc = smc_clc_send_accept(new_smc, local_contact); if (rc) goto out_err; @@ -839,7 +844,6 @@ static void smc_listen_work(struct work_struct *work) } smc_tx_init(new_smc); - smc_rx_init(new_smc); out_connected: sk_refcnt_debug_inc(newsmcsk); diff --git a/net/smc/smc.h b/net/smc/smc.h index ee5fbea24549..6e44313e4467 100644 --- a/net/smc/smc.h +++ b/net/smc/smc.h @@ -164,6 +164,7 @@ struct smc_connection { #ifndef KERNEL_HAS_ATOMIC64 spinlock_t acurs_lock; /* protect cursors */ #endif + struct work_struct close_work; /* peer sent some closing */ }; struct smc_sock { /* smc sock container */ diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index 4c9c2f6cd021..a7294edbc221 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -217,8 +217,13 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, smc->sk.sk_err = ECONNRESET; conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; } - if (smc_cdc_rxed_any_close_or_senddone(conn)) - smc_close_passive_received(smc); + if (smc_cdc_rxed_any_close_or_senddone(conn)) { + smc->sk.sk_shutdown |= RCV_SHUTDOWN; + if (smc->clcsock && smc->clcsock->sk) + smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; + sock_set_flag(&smc->sk, SOCK_DONE); + schedule_work(&conn->close_work); + } /* piggy backed tx info */ /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */ diff --git a/net/smc/smc_close.c b/net/smc/smc_close.c index 67a71d170bed..388503b78228 100644 --- a/net/smc/smc_close.c +++ b/net/smc/smc_close.c @@ -117,7 +117,6 @@ void smc_close_active_abort(struct smc_sock *smc) struct smc_cdc_conn_state_flags *txflags = &smc->conn.local_tx_ctrl.conn_state_flags; - bh_lock_sock(&smc->sk); smc->sk.sk_err = ECONNABORTED; if (smc->clcsock && smc->clcsock->sk) { smc->clcsock->sk->sk_err = ECONNABORTED; @@ -125,6 +124,7 @@ void smc_close_active_abort(struct smc_sock *smc) } switch (smc->sk.sk_state) { case SMC_INIT: + case SMC_ACTIVE: smc->sk.sk_state = SMC_PEERABORTWAIT; break; case SMC_APPCLOSEWAIT1: @@ -161,7 +161,6 @@ void smc_close_active_abort(struct smc_sock *smc) } sock_set_flag(&smc->sk, SOCK_DEAD); - bh_unlock_sock(&smc->sk); smc->sk.sk_state_change(&smc->sk); } @@ -185,7 +184,7 @@ again: case SMC_INIT: sk->sk_state = SMC_CLOSED; if (smc->smc_listen_work.func) - flush_work(&smc->smc_listen_work); + cancel_work_sync(&smc->smc_listen_work); sock_put(sk); break; case SMC_LISTEN: @@ -198,7 +197,7 @@ again: } release_sock(sk); smc_close_cleanup_listen(sk); - flush_work(&smc->tcp_listen_work); + cancel_work_sync(&smc->smc_listen_work); lock_sock(sk); break; case SMC_ACTIVE: @@ -306,22 +305,27 @@ static void smc_close_passive_abort_received(struct smc_sock *smc) /* Some kind of closing has been received: peer_conn_closed, peer_conn_abort, * or peer_done_writing. - * Called under tasklet context. */ -void smc_close_passive_received(struct smc_sock *smc) +static void smc_close_passive_work(struct work_struct *work) { - struct smc_cdc_conn_state_flags *rxflags = - &smc->conn.local_rx_ctrl.conn_state_flags; + struct smc_connection *conn = container_of(work, + struct smc_connection, + close_work); + struct smc_sock *smc = container_of(conn, struct smc_sock, conn); + struct smc_cdc_conn_state_flags *rxflags; struct sock *sk = &smc->sk; int old_state; - sk->sk_shutdown |= RCV_SHUTDOWN; - if (smc->clcsock && smc->clcsock->sk) - smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN; - sock_set_flag(&smc->sk, SOCK_DONE); - + lock_sock(&smc->sk); old_state = sk->sk_state; + if (!conn->alert_token_local) { + /* abnormal termination */ + smc_close_active_abort(smc); + goto wakeup; + } + + rxflags = &smc->conn.local_rx_ctrl.conn_state_flags; if (rxflags->peer_conn_abort) { smc_close_passive_abort_received(smc); goto wakeup; @@ -373,11 +377,12 @@ wakeup: sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */ if ((sk->sk_state == SMC_CLOSED) && - (sock_flag(sk, SOCK_DEAD) || (old_state == SMC_INIT))) { + (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) { smc_conn_free(&smc->conn); schedule_delayed_work(&smc->sock_put_work, SMC_CLOSE_SOCK_PUT_DELAY); } + release_sock(&smc->sk); } void smc_close_sock_put_work(struct work_struct *work) @@ -442,3 +447,9 @@ again: sk->sk_state_change(&smc->sk); return rc; } + +/* Initialize close properties on connection establishment. */ +void smc_close_init(struct smc_sock *smc) +{ + INIT_WORK(&smc->conn.close_work, smc_close_passive_work); +} diff --git a/net/smc/smc_close.h b/net/smc/smc_close.h index bc9a2df3633c..4a3d99a8d7cb 100644 --- a/net/smc/smc_close.h +++ b/net/smc/smc_close.h @@ -21,8 +21,8 @@ void smc_close_wake_tx_prepared(struct smc_sock *smc); void smc_close_active_abort(struct smc_sock *smc); int smc_close_active(struct smc_sock *smc); -void smc_close_passive_received(struct smc_sock *smc); void smc_close_sock_put_work(struct work_struct *work); int smc_close_shutdown_write(struct smc_sock *smc); +void smc_close_init(struct smc_sock *smc); #endif /* SMC_CLOSE_H */ diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 0eac633fb354..65020e93ff21 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -316,7 +316,7 @@ void smc_lgr_terminate(struct smc_link_group *lgr) smc = container_of(conn, struct smc_sock, conn); sock_hold(&smc->sk); __smc_lgr_unregister_conn(conn); - smc_close_active_abort(smc); + schedule_work(&conn->close_work); sock_put(&smc->sk); node = rb_first(&lgr->conns_all); }