diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index 593f586545eb..39123c06a566 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -119,6 +119,7 @@ enum rxrpc_recvmsg_trace { rxrpc_recvmsg_full, rxrpc_recvmsg_hole, rxrpc_recvmsg_next, + rxrpc_recvmsg_requeue, rxrpc_recvmsg_return, rxrpc_recvmsg_terminal, rxrpc_recvmsg_to_be_accepted, @@ -277,6 +278,7 @@ enum rxrpc_congest_change { EM(rxrpc_recvmsg_full, "FULL") \ EM(rxrpc_recvmsg_hole, "HOLE") \ EM(rxrpc_recvmsg_next, "NEXT") \ + EM(rxrpc_recvmsg_requeue, "REQU") \ EM(rxrpc_recvmsg_return, "RETN") \ EM(rxrpc_recvmsg_terminal, "TERM") \ EM(rxrpc_recvmsg_to_be_accepted, "TBAC") \ diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c index 199b46e93e64..7fb59c3f1542 100644 --- a/net/rxrpc/af_rxrpc.c +++ b/net/rxrpc/af_rxrpc.c @@ -290,10 +290,11 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock, cp.exclusive = false; cp.service_id = srx->srx_service; call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, gfp); + /* The socket has been unlocked. */ if (!IS_ERR(call)) call->notify_rx = notify_rx; - release_sock(&rx->sk); + mutex_unlock(&call->user_mutex); _leave(" = %p", call); return call; } @@ -310,7 +311,10 @@ EXPORT_SYMBOL(rxrpc_kernel_begin_call); void rxrpc_kernel_end_call(struct socket *sock, struct rxrpc_call *call) { _enter("%d{%d}", call->debug_id, atomic_read(&call->usage)); + + mutex_lock(&call->user_mutex); rxrpc_release_call(rxrpc_sk(sock->sk), call); + mutex_unlock(&call->user_mutex); rxrpc_put_call(call, rxrpc_call_put_kernel); } EXPORT_SYMBOL(rxrpc_kernel_end_call); @@ -450,14 +454,16 @@ static int rxrpc_sendmsg(struct socket *sock, struct msghdr *m, size_t len) case RXRPC_SERVER_BOUND: case RXRPC_SERVER_LISTENING: ret = rxrpc_do_sendmsg(rx, m, len); - break; + /* The socket has been unlocked */ + goto out; default: ret = -EINVAL; - break; + goto error_unlock; } error_unlock: release_sock(&rx->sk); +out: _leave(" = %d", ret); return ret; } diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 12be432be9b2..26a7b1db1361 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -467,6 +467,7 @@ struct rxrpc_call { struct rxrpc_connection *conn; /* connection carrying call */ struct rxrpc_peer *peer; /* Peer record for remote address */ struct rxrpc_sock __rcu *socket; /* socket responsible */ + struct mutex user_mutex; /* User access mutex */ ktime_t ack_at; /* When deferred ACK needs to happen */ ktime_t resend_at; /* When next resend needs to happen */ ktime_t ping_at; /* When next to send a ping */ diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c index 7c4c64ab8da2..0ed181f53f32 100644 --- a/net/rxrpc/call_accept.c +++ b/net/rxrpc/call_accept.c @@ -323,6 +323,8 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx, * * If we want to report an error, we mark the skb with the packet type and * abort code and return NULL. + * + * The call is returned with the user access mutex held. */ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local, struct rxrpc_connection *conn, @@ -371,6 +373,18 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local, trace_rxrpc_receive(call, rxrpc_receive_incoming, sp->hdr.serial, sp->hdr.seq); + /* Lock the call to prevent rxrpc_kernel_send/recv_data() and + * sendmsg()/recvmsg() inconveniently stealing the mutex once the + * notification is generated. + * + * The BUG should never happen because the kernel should be well + * behaved enough not to access the call before the first notification + * event and userspace is prevented from doing so until the state is + * appropriate. + */ + if (!mutex_trylock(&call->user_mutex)) + BUG(); + /* Make the call live. */ rxrpc_incoming_call(rx, call, skb); conn = call->conn; @@ -429,10 +443,12 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local, /* * handle acceptance of a call by userspace * - assign the user call ID to the call at the front of the queue + * - called with the socket locked. */ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, unsigned long user_call_ID, rxrpc_notify_rx_t notify_rx) + __releases(&rx->sk.sk_lock.slock) { struct rxrpc_call *call; struct rb_node *parent, **pp; @@ -446,6 +462,7 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, if (list_empty(&rx->to_be_accepted)) { write_unlock(&rx->call_lock); + release_sock(&rx->sk); kleave(" = -ENODATA [empty]"); return ERR_PTR(-ENODATA); } @@ -470,10 +487,39 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, */ call = list_entry(rx->to_be_accepted.next, struct rxrpc_call, accept_link); + write_unlock(&rx->call_lock); + + /* We need to gain the mutex from the interrupt handler without + * upsetting lockdep, so we have to release it there and take it here. + * We are, however, still holding the socket lock, so other accepts + * must wait for us and no one can add the user ID behind our backs. + */ + if (mutex_lock_interruptible(&call->user_mutex) < 0) { + release_sock(&rx->sk); + kleave(" = -ERESTARTSYS"); + return ERR_PTR(-ERESTARTSYS); + } + + write_lock(&rx->call_lock); list_del_init(&call->accept_link); sk_acceptq_removed(&rx->sk); rxrpc_see_call(call); + /* Find the user ID insertion point. */ + pp = &rx->calls.rb_node; + parent = NULL; + while (*pp) { + parent = *pp; + call = rb_entry(parent, struct rxrpc_call, sock_node); + + if (user_call_ID < call->user_call_ID) + pp = &(*pp)->rb_left; + else if (user_call_ID > call->user_call_ID) + pp = &(*pp)->rb_right; + else + BUG(); + } + write_lock_bh(&call->state_lock); switch (call->state) { case RXRPC_CALL_SERVER_ACCEPTING: @@ -499,6 +545,7 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, write_unlock(&rx->call_lock); rxrpc_notify_socket(call); rxrpc_service_prealloc(rx, GFP_KERNEL); + release_sock(&rx->sk); _leave(" = %p{%d}", call, call->debug_id); return call; @@ -515,6 +562,7 @@ struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx, write_unlock(&rx->call_lock); out: rxrpc_service_prealloc(rx, GFP_KERNEL); + release_sock(&rx->sk); _leave(" = %d", ret); return ERR_PTR(ret); } diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c index 8b94db3c9b2e..d79cd36987a9 100644 --- a/net/rxrpc/call_object.c +++ b/net/rxrpc/call_object.c @@ -115,6 +115,7 @@ struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp) if (!call->rxtx_annotations) goto nomem_2; + mutex_init(&call->user_mutex); setup_timer(&call->timer, rxrpc_call_timer_expired, (unsigned long)call); INIT_WORK(&call->processor, &rxrpc_process_call); @@ -194,14 +195,16 @@ static void rxrpc_start_call_timer(struct rxrpc_call *call) } /* - * set up a call for the given data - * - called in process context with IRQs enabled + * Set up a call for the given parameters. + * - Called with the socket lock held, which it must release. + * - If it returns a call, the call's lock will need releasing by the caller. */ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, struct rxrpc_conn_parameters *cp, struct sockaddr_rxrpc *srx, unsigned long user_call_ID, gfp_t gfp) + __releases(&rx->sk.sk_lock.slock) { struct rxrpc_call *call, *xcall; struct rb_node *parent, **pp; @@ -212,6 +215,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, call = rxrpc_alloc_client_call(srx, gfp); if (IS_ERR(call)) { + release_sock(&rx->sk); _leave(" = %ld", PTR_ERR(call)); return call; } @@ -219,6 +223,11 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage), here, (const void *)user_call_ID); + /* We need to protect a partially set up call against the user as we + * will be acting outside the socket lock. + */ + mutex_lock(&call->user_mutex); + /* Publish the call, even though it is incompletely set up as yet */ write_lock(&rx->call_lock); @@ -250,6 +259,9 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, list_add_tail(&call->link, &rxrpc_calls); write_unlock(&rxrpc_call_lock); + /* From this point on, the call is protected by its own lock. */ + release_sock(&rx->sk); + /* Set up or get a connection record and set the protocol parameters, * including channel number and call ID. */ @@ -279,6 +291,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, */ error_dup_user_ID: write_unlock(&rx->call_lock); + release_sock(&rx->sk); ret = -EEXIST; error: @@ -287,6 +300,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage), here, ERR_PTR(ret)); rxrpc_release_call(rx, call); + mutex_unlock(&call->user_mutex); rxrpc_put_call(call, rxrpc_call_put); _leave(" = %d", ret); return ERR_PTR(ret); diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 78ec33477adf..9f4cfa25af7c 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -1194,6 +1194,7 @@ void rxrpc_data_ready(struct sock *udp_sk) goto reject_packet; } rxrpc_send_ping(call, skb, skew); + mutex_unlock(&call->user_mutex); } rxrpc_input_call_packet(call, skb, skew); diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c index f3a688e10843..22447dbcc380 100644 --- a/net/rxrpc/recvmsg.c +++ b/net/rxrpc/recvmsg.c @@ -487,6 +487,20 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0); + /* We're going to drop the socket lock, so we need to lock the call + * against interference by sendmsg. + */ + if (!mutex_trylock(&call->user_mutex)) { + ret = -EWOULDBLOCK; + if (flags & MSG_DONTWAIT) + goto error_requeue_call; + ret = -ERESTARTSYS; + if (mutex_lock_interruptible(&call->user_mutex) < 0) + goto error_requeue_call; + } + + release_sock(&rx->sk); + if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) BUG(); @@ -502,7 +516,7 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, &call->user_call_ID); } if (ret < 0) - goto error; + goto error_unlock_call; } if (msg->msg_name) { @@ -533,12 +547,12 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, } if (ret < 0) - goto error; + goto error_unlock_call; if (call->state == RXRPC_CALL_COMPLETE) { ret = rxrpc_recvmsg_term(call, msg); if (ret < 0) - goto error; + goto error_unlock_call; if (!(flags & MSG_PEEK)) rxrpc_release_call(rx, call); msg->msg_flags |= MSG_EOR; @@ -551,8 +565,21 @@ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, msg->msg_flags &= ~MSG_MORE; ret = copied; -error: +error_unlock_call: + mutex_unlock(&call->user_mutex); rxrpc_put_call(call, rxrpc_call_put); + trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret); + return ret; + +error_requeue_call: + if (!(flags & MSG_PEEK)) { + write_lock_bh(&rx->recvmsg_lock); + list_add(&call->recvmsg_link, &rx->recvmsg_q); + write_unlock_bh(&rx->recvmsg_lock); + trace_rxrpc_recvmsg(call, rxrpc_recvmsg_requeue, 0, 0, 0, 0); + } else { + rxrpc_put_call(call, rxrpc_call_put); + } error_no_call: release_sock(&rx->sk); trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret); @@ -609,7 +636,7 @@ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call, iov.iov_len = size - *_offset; iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset); - lock_sock(sock->sk); + mutex_lock(&call->user_mutex); switch (call->state) { case RXRPC_CALL_CLIENT_RECV_REPLY: @@ -648,7 +675,7 @@ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call, read_phase_complete: ret = 1; out: - release_sock(sock->sk); + mutex_unlock(&call->user_mutex); _leave(" = %d [%zu,%d]", ret, *_offset, *_abort); return ret; diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index 0a6ef217aa8a..31c1538c1a8d 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -59,9 +59,12 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx, } trace_rxrpc_transmit(call, rxrpc_transmit_wait); - release_sock(&rx->sk); + mutex_unlock(&call->user_mutex); *timeo = schedule_timeout(*timeo); - lock_sock(&rx->sk); + if (mutex_lock_interruptible(&call->user_mutex) < 0) { + ret = sock_intr_errno(*timeo); + break; + } } remove_wait_queue(&call->waitq, &myself); @@ -171,7 +174,7 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb, /* * send data through a socket * - must be called in process context - * - caller holds the socket locked + * - The caller holds the call user access mutex, but not the socket lock. */ static int rxrpc_send_data(struct rxrpc_sock *rx, struct rxrpc_call *call, @@ -437,10 +440,13 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg, /* * Create a new client call for sendmsg(). + * - Called with the socket lock held, which it must release. + * - If it returns a call, the call's lock will need releasing by the caller. */ static struct rxrpc_call * rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, unsigned long user_call_ID, bool exclusive) + __releases(&rx->sk.sk_lock.slock) { struct rxrpc_conn_parameters cp; struct rxrpc_call *call; @@ -450,8 +456,10 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, _enter(""); - if (!msg->msg_name) + if (!msg->msg_name) { + release_sock(&rx->sk); return ERR_PTR(-EDESTADDRREQ); + } key = rx->key; if (key && !rx->key->payload.data[0]) @@ -464,6 +472,7 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, cp.exclusive = rx->exclusive | exclusive; cp.service_id = srx->srx_service; call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL); + /* The socket is now unlocked */ _leave(" = %p\n", call); return call; @@ -475,6 +484,7 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, * - the socket may be either a client socket or a server socket */ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) + __releases(&rx->sk.sk_lock.slock) { enum rxrpc_command cmd; struct rxrpc_call *call; @@ -488,12 +498,14 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code, &exclusive); if (ret < 0) - return ret; + goto error_release_sock; if (cmd == RXRPC_CMD_ACCEPT) { + ret = -EINVAL; if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) - return -EINVAL; + goto error_release_sock; call = rxrpc_accept_call(rx, user_call_ID, NULL); + /* The socket is now unlocked. */ if (IS_ERR(call)) return PTR_ERR(call); rxrpc_put_call(call, rxrpc_call_put); @@ -502,12 +514,29 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) call = rxrpc_find_call_by_user_ID(rx, user_call_ID); if (!call) { + ret = -EBADSLT; if (cmd != RXRPC_CMD_SEND_DATA) - return -EBADSLT; + goto error_release_sock; + ret = -EBUSY; + if (call->state == RXRPC_CALL_UNINITIALISED || + call->state == RXRPC_CALL_CLIENT_AWAIT_CONN || + call->state == RXRPC_CALL_SERVER_PREALLOC || + call->state == RXRPC_CALL_SERVER_SECURING || + call->state == RXRPC_CALL_SERVER_ACCEPTING) + goto error_release_sock; call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID, exclusive); + /* The socket is now unlocked... */ if (IS_ERR(call)) return PTR_ERR(call); + /* ... and we have the call lock. */ + } else { + ret = mutex_lock_interruptible(&call->user_mutex); + release_sock(&rx->sk); + if (ret < 0) { + ret = -ERESTARTSYS; + goto error_put; + } } _debug("CALL %d USR %lx ST %d on CONN %p", @@ -535,9 +564,15 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) ret = rxrpc_send_data(rx, call, msg, len); } + mutex_unlock(&call->user_mutex); +error_put: rxrpc_put_call(call, rxrpc_call_put); _leave(" = %d", ret); return ret; + +error_release_sock: + release_sock(&rx->sk); + return ret; } /** @@ -562,7 +597,7 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call, ASSERTCMP(msg->msg_name, ==, NULL); ASSERTCMP(msg->msg_control, ==, NULL); - lock_sock(sock->sk); + mutex_lock(&call->user_mutex); _debug("CALL %d USR %lx ST %d on CONN %p", call->debug_id, call->user_call_ID, call->state, call->conn); @@ -577,7 +612,7 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call, ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len); } - release_sock(sock->sk); + mutex_unlock(&call->user_mutex); _leave(" = %d", ret); return ret; } @@ -598,12 +633,12 @@ void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call, { _enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why); - lock_sock(sock->sk); + mutex_lock(&call->user_mutex); if (rxrpc_abort_call(why, call, 0, abort_code, error)) rxrpc_send_abort_packet(call); - release_sock(sock->sk); + mutex_unlock(&call->user_mutex); _leave(""); }