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Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net 2/2] rxrpc: Fix missing notification From: David Howells To: netdev@vger.kernel.org Cc: Gerry Seidman , Marc Dionne , dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Mon, 08 Jun 2020 19:50:01 +0100 Message-ID: <159164220145.2758133.3370434050398146640.stgit@warthog.procyon.org.uk> In-Reply-To: <159164218727.2758133.1046957228494479308.stgit@warthog.procyon.org.uk> References: <159164218727.2758133.1046957228494479308.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.22 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Under some circumstances, rxrpc will fail a transmit a packet through the underlying UDP socket (ie. UDP sendmsg returns an error). This may result in a call getting stuck. In the instance being seen, where AFS tries to send a probe to the Volume Location server, tracepoints show the UDP Tx failure (in this case returing error 99 EADDRNOTAVAIL) and then nothing more: afs_make_vl_call: c=0000015d VL.GetCapabilities rxrpc_call: c=0000015d NWc u=1 sp=rxrpc_kernel_begin_call+0x106/0x170 [rxrpc] a=00000000dd89ee8a rxrpc_call: c=0000015d Gus u=2 sp=rxrpc_new_client_call+0x14f/0x580 [rxrpc] a=00000000e20e4b08 rxrpc_call: c=0000015d SEE u=2 sp=rxrpc_activate_one_channel+0x7b/0x1c0 [rxrpc] a=00000000e20e4b08 rxrpc_call: c=0000015d CON u=2 sp=rxrpc_kernel_begin_call+0x106/0x170 [rxrpc] a=00000000e20e4b08 rxrpc_tx_fail: c=0000015d r=1 ret=-99 CallDataNofrag The problem is that if the initial packet fails and the retransmission timer hasn't been started, the call is set to completed and an error is returned from rxrpc_send_data_packet() to rxrpc_queue_packet(). Though rxrpc_instant_resend() is called, this does nothing because the call is marked completed. So rxrpc_notify_socket() isn't called and the error is passed back up to rxrpc_send_data(), rxrpc_kernel_send_data() and thence to afs_make_call() and afs_vl_get_capabilities() where it is simply ignored because it is assumed that the result of a probe will be collected asynchronously. Fileserver probing is similarly affected via afs_fs_get_capabilities(). Fix this by always issuing a notification in __rxrpc_set_call_completion() if it shifts a call to the completed state, even if an error is also returned to the caller through the function return value. Also put in a little bit of optimisation to avoid taking the call state_lock and disabling softirqs if the call is already in the completed state and remove some now redundant rxrpc_notify_socket() calls. Fixes: f5c17aaeb2ae ("rxrpc: Calls should only have one terminal state") Reported-by: Gerry Seidman Signed-off-by: David Howells Reviewed-by: Marc Dionne --- net/rxrpc/call_event.c | 1 - net/rxrpc/conn_event.c | 7 +++---- net/rxrpc/input.c | 7 ++----- net/rxrpc/peer_event.c | 4 +--- net/rxrpc/recvmsg.c | 21 +++++++++++++-------- net/rxrpc/sendmsg.c | 6 ++---- 6 files changed, 21 insertions(+), 25 deletions(-) diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c index 2a65ac41055f..61a51c251e1b 100644 --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -320,7 +320,6 @@ void rxrpc_process_call(struct work_struct *work) if (call->state == RXRPC_CALL_COMPLETE) { del_timer_sync(&call->timer); - rxrpc_notify_socket(call); goto out_put; } diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c index 06fcff2ebbba..447f55ca6886 100644 --- a/net/rxrpc/conn_event.c +++ b/net/rxrpc/conn_event.c @@ -173,10 +173,9 @@ static void rxrpc_abort_calls(struct rxrpc_connection *conn, else trace_rxrpc_rx_abort(call, serial, conn->abort_code); - if (rxrpc_set_call_completion(call, compl, - conn->abort_code, - conn->error)) - rxrpc_notify_socket(call); + rxrpc_set_call_completion(call, compl, + conn->abort_code, + conn->error); } } diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 3be4177baf70..299ac98e9754 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -275,7 +275,6 @@ static bool rxrpc_end_tx_phase(struct rxrpc_call *call, bool reply_begun, case RXRPC_CALL_SERVER_AWAIT_ACK: __rxrpc_call_completed(call); - rxrpc_notify_socket(call); state = call->state; break; @@ -1013,9 +1012,8 @@ static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb) _proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code); - if (rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, - abort_code, -ECONNABORTED)) - rxrpc_notify_socket(call); + rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED, + abort_code, -ECONNABORTED); } /* @@ -1102,7 +1100,6 @@ static void rxrpc_input_implicit_end_call(struct rxrpc_sock *rx, spin_lock(&rx->incoming_lock); __rxrpc_disconnect_call(conn, call); spin_unlock(&rx->incoming_lock); - rxrpc_notify_socket(call); } /* diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c index b1449d971883..4704a8dceced 100644 --- a/net/rxrpc/peer_event.c +++ b/net/rxrpc/peer_event.c @@ -289,9 +289,7 @@ static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error, hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) { rxrpc_see_call(call); - if (call->state < RXRPC_CALL_COMPLETE && - rxrpc_set_call_completion(call, compl, 0, -error)) - rxrpc_notify_socket(call); + rxrpc_set_call_completion(call, compl, 0, -error); } } diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c index 6c4ba4224ddc..2989742a4aa1 100644 --- a/net/rxrpc/recvmsg.c +++ b/net/rxrpc/recvmsg.c @@ -73,6 +73,7 @@ bool __rxrpc_set_call_completion(struct rxrpc_call *call, call->state = RXRPC_CALL_COMPLETE; trace_rxrpc_call_complete(call); wake_up(&call->waitq); + rxrpc_notify_socket(call); return true; } return false; @@ -83,11 +84,13 @@ bool rxrpc_set_call_completion(struct rxrpc_call *call, u32 abort_code, int error) { - bool ret; + bool ret = false; - write_lock_bh(&call->state_lock); - ret = __rxrpc_set_call_completion(call, compl, abort_code, error); - write_unlock_bh(&call->state_lock); + if (call->state < RXRPC_CALL_COMPLETE) { + write_lock_bh(&call->state_lock); + ret = __rxrpc_set_call_completion(call, compl, abort_code, error); + write_unlock_bh(&call->state_lock); + } return ret; } @@ -101,11 +104,13 @@ bool __rxrpc_call_completed(struct rxrpc_call *call) bool rxrpc_call_completed(struct rxrpc_call *call) { - bool ret; + bool ret = false; - write_lock_bh(&call->state_lock); - ret = __rxrpc_call_completed(call); - write_unlock_bh(&call->state_lock); + if (call->state < RXRPC_CALL_COMPLETE) { + write_lock_bh(&call->state_lock); + ret = __rxrpc_call_completed(call); + write_unlock_bh(&call->state_lock); + } return ret; } diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index 5dd9ba000c00..1304b8608f56 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -261,10 +261,8 @@ static int rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call, case -ENETUNREACH: case -EHOSTUNREACH: case -ECONNREFUSED: - if (rxrpc_set_call_completion(call, - RXRPC_CALL_LOCAL_ERROR, - 0, ret)) - rxrpc_notify_socket(call); + rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, + 0, ret); goto out; } _debug("need instant resend %d", ret);