[tor-bugs] #15618 [Core Tor/Tor]: Tried to establish rendezvous on non-OR circuit with purpose Acting as rendevous (pending)

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#15618: Tried to establish rendezvous on non-OR circuit with purpose Acting as
rendevous (pending)
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  dgoulet
     Type:  defect                               |         Status:
                                                 |  needs_information
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  unspecified
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-hs needs-insight needs-          |  Actual Points:
  diagnosis                                      |
Parent ID:                                       |         Points:  1
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by s7r):

 I checked the relay for maintenance just now and surprise: there were over
 100 [warn] Tried to establish rendezvous on non-OR circuit with purpose
 Acting as rendevous (pending) in the log file and continued to appear, so
 switched to log level debug and sent a HUP signal to the Tor daemon to see
 in depth what is going on.

 We can be sure it's what dgoulet indicated at comment:27 (two
 `ESTABLISH_RENDEZVOUS` cells on the same circuit). I am providing some
 debug logs, filtered only for the circuit ID we are interested in since
 the original file is very large:
 {{{
 Oct 31 00:02:47.000 [debug] command_process_create_cell: Got a CREATE cell
 for circ_id 3320782221 on channel 496023 (0x805b1cd00)
 Oct 31 00:02:47.000 [debug] circuit_get_by_circid_channel_impl:
 circuit_get_by_circid_channel_impl() found nothing for circ_id 3320782221,
 channel ID 496023 (0x805b1cd00)
 Oct 31 00:02:47.000 [debug] circuitmux_attach_circuit: Attaching circuit
 3320782221 on channel 496023 to cmux 0x80830a9a0
 Oct 31 00:02:47.000 [debug] circuit_get_by_circid_channel_impl:
 circuit_get_by_circid_channel_impl() returning circuit 0x8052ce4c0 for
 circ_id 3320782221, channel ID 496023 (0x805b1cd00)
 Oct 31 00:02:47.000 [info] rend_mid_establish_rendezvous: Received an
 ESTABLISH_RENDEZVOUS request on circuit 3320782221
 Oct 31 00:02:47.000 [info] rend_mid_establish_rendezvous: Established
 rendezvous point on circuit 3320782221 for cookie D21DCC69
 Oct 31 00:02:49.000 [debug] circuit_get_by_circid_channel_impl:
 circuit_get_by_circid_channel_impl() returning circuit 0x8052ce4c0 for
 circ_id 3320782221, channel ID 496023 (0x805b1cd00)
 Oct 31 00:02:49.000 [info] rend_mid_establish_rendezvous: Received an
 ESTABLISH_RENDEZVOUS request on circuit 3320782221
 Oct 31 00:02:49.000 [warn] Tried to establish rendezvous on non-OR circuit
 with purpose Acting as rendevous (pending)
 Oct 31 00:02:49.000 [debug] circuit_get_by_circid_channel_impl:
 circuit_get_by_circid_channel_impl() returning circuit 0x8052ce4c0 for
 circ_id 3320782221, channel  ID 496023 (0x805b1cd00)
 Oct 31 00:02:49.000 [info] circuit_mark_for_close_: Circuit 0 (id: 0)
 marked for close at src/or/rendmid.c:272 (orig reason: 1, new reason: 1)
 Oct 31 00:02:49.000 [debug] channel_send_destroy: Sending destroy (circID
 3320782221) on channel 0x805b1cd00 (global ID 496023)
 }}}

 At 02:47 we successfully established rendezvous with cookie D21DCC69 on
 this circuit, and at 02.49 another `ESTABLISH_RENDEZVOUS` was sent on the
 same circuit which made it mark the circuit for close
 (src/or/rendmid.c:272).

 I still wonder why sometimes this happens heavily, like today (over 300
 warnings till now) and sometimes not. The relay has low consensus weight
 and the Exit flag, so its probability to be chosen as RP should be 0 if we
 consider its flags and 0.00something if we only consider its consensus
 weight.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15618#comment:33>
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