[tor-bugs] #1890 [Tor Relay]: Tor failed to make a consensus 2010/08/29 17:00

Tor Bug Tracker & Wiki torproject-admin at torproject.org
Tue Aug 31 22:04:50 UTC 2010


#1890: Tor failed to make a consensus 2010/08/29 17:00
-----------------------+----------------------------------------------------
 Reporter:  Sebastian  |       Owner:                    
     Type:  defect     |      Status:  new               
 Priority:  major      |   Milestone:  Tor: 0.2.2.x-final
Component:  Tor Relay  |     Version:                    
 Keywords:             |      Parent:                    
-----------------------+----------------------------------------------------

Comment(by arma):

 All the authorities started their voting process at :50:00. They started
 uploading their votes to various places.

 While gabelmoo was computing its vote, it moved its clock forward by 2
 minutes and 20 seconds.

 moria1 finished uploading its vote to gabelmoo at:
 Aug 29 12:51:47.089 [notice] Uploaded a vote to dirserver
 80.190.246.100:8180
 but I don't see this vote appearing in gabelmoo's logs. If it did, we
 could use it to figure out gabelmoo's clock offset.

 So question 1: How come it doesn't appear?

 What happened to gabelmoo during this time? It wasn't just fixing its
 clock, because it took 1 minute 43 seconds longer to upload moria1's vote
 to it than it took to upload moria1's vote to the other authorities. It
 looks like it was having some serious load or network issues.

 Then a little while later gabelmoo says
 Aug 29 18:53:01.925 [notice] Uploaded a vote to dirserver 128.31.0.34:9131

 which corresponds to this line in moria1's log:
 Aug 29 12:55:01.424 [info] connection_dir_client_reached_eof(): Got votes
 (size 827573) from server 80.190.246.100:8180
 Aug 29 12:55:01.496 [info] update_consensus_router_descriptor_downloads():
 Learned about Unnamed (2010-08-29 16:48:15 vs 2010-08-29 16:53:28) from
 gabelmoo's vote (known)
 Aug 29 12:55:01.596 [info] connection_dir_client_reached_eof(): Added
 vote(s) successfully [msg: ok]

 Except my theory might be wrong, because moria1 seems to think it
 *downloaded* the vote, and gabelmoo seems to think it *uploaded* the vote.
 These cannot both be true. I didn't find any hints in moria1's logs of
 receiving an uploaded vote from gabelmoo, but I don't know where to look
 because I think gabelmoo's time is wrong.

 It would be good to get (at least notice-level) logs from all the other
 authorities so we can see if we can match up timings and figure out what
 time gabelmoo actually did various things.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/1890#comment:6>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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