Re: [tor-bugs] #18116 [Tor]: abort in circuitmux_detach_all_circuits on Tor Browser exit with stem scripts running

["Tor Bug Tracker & Wiki" <blackhole@xxxxxxxxxxxxxx>]

#18116: abort in circuitmux_detach_all_circuits on Tor Browser exit with stem
scripts running
-------------------------------------+------------------------------------
 Reporter:  teor                     |          Owner:  andrea
     Type:  defect                   |         Status:  assigned
 Priority:  Medium                   |      Milestone:  Tor: 0.2.8.x-final
Component:  Tor                      |        Version:
 Severity:  Normal                   |     Resolution:
 Keywords:  crash TorCoreTeam201602  |  Actual Points:
Parent ID:  #18117                   |         Points:
  Sponsor:                           |
-------------------------------------+------------------------------------

Comment (by teor):

 The bug is reproducible, but it's a race condition, which means getting
 the timing right can be difficult. I think it happens if tor is terminated
 just after stem calls close_circuit(), but before some cleanup is done
 (perhaps the next second_elapsed_callback()?).

 To reproduce:
 * start a tor client
 * run `python bug18116_stem.py [ControlPort]`
 * kill tor when the stem script asks you to

 To increase your chances of triggering the race condition:
 * increase N_ATTEMPTS in the script,
 * run multiple scripts against the same tor instance,
 * terminate tor after they've each made a few connections.
 (You only have to get the timing right with one script to trigger the
 bug.)

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18116#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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