[tor-bugs] #8185 [Core Tor/Tor]: circuit_package_relay_cell(): Bug: outgoing relay cell has n_chan==NULL. Dropping.

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#8185: circuit_package_relay_cell(): Bug: outgoing relay cell has n_chan==NULL.
Dropping.
------------------------------------------+--------------------------------
 Reporter:  mr-4                          |          Owner:
     Type:  defect                        |         Status:
 Priority:  Medium                        |  needs_information
Component:  Core Tor/Tor                  |      Milestone:  Tor:
 Severity:  Normal                        |  0.2.9.x-final
 Keywords:  tor-relay, TorCoreTeam201604  |        Version:  Tor:
Parent ID:                                |  0.2.4.9-alpha
 Reviewer:  isis                          |     Resolution:
                                          |  Actual Points:
                                          |         Points:  medium
                                          |        Sponsor:
------------------------------------------+--------------------------------

Comment (by cypherpunks):

 Replying to [comment:29 isis]:
 > On 0.2.8.x, sending a destroy cell from the entry to the client while
 the client is trying to send data still doesn't seem to trigger this for
 me…
 >
 > Since a bunch of the code for marking circuits for close and freeing
 them changed in 0.2.8, I agree that trying to track this bug down in N
 different tor versions is probably going to be too confusing.  We should
 probably just focus on trying to find it in `maint-0.2.8`?
 >
 > I'm putting this ticket back into 'needs_information' state, and
 hopefully more people will come along and try to figure out where this bug
 is coming from.

 {{{
      if (!chan) {
        log_warn(LD_BUG,"outgoing relay cell sent from %s:%d has
 n_chan==NULL."
                 " Dropping.", filename, lineno);
 +      if (circ->marked_for_close) {
 +        log_warn(LD_BUG,
 +                 "Circuit n_circ_id %u was marked for close at %s:%d"
 +                 " for reason %d", (unsigned)circ->n_circ_id,
 +                 circ->marked_for_close_file, circ->marked_for_close,
 +                 circ->marked_for_close_orig_reason);
 +      }
        return 0; /* just drop it */
      }
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8185#comment:30>
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