[tor-bugs] #21084 [Core Tor/Tor]: sometimes we call circuit has_opened() more than 2 times on client side

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#21084: sometimes we call circuit has_opened() more than 2 times on client side
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 Reporter:  s7r           |          Owner:  dgoulet
     Type:  defect        |         Status:  needs_information
 Priority:  Medium        |      Milestone:  Tor: 0.3.0.x-final
Component:  Core Tor/Tor  |        Version:  Tor: 0.3.0.1-alpha
 Severity:  Normal        |     Resolution:
 Keywords:  tor-hs        |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
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Comment (by dgoulet):

 Replying to [comment:5 s7r]:
 > Above we have two different 5 hops circuits with different middle hops
 (2 and 3) but the same endpoints, for which `circuit has_opened()` was
 called 3 times. Since that log line is totally missing, the client may not
 have received a NACK. I am thinking of some weird race conditions, because
 we are only able to catch this behavior when quite a large amount of
 isolated requests are sent to the same hidden service in a very short
 period of time.

 Is there a way you are able to learn the introduction point of the HS you
 are trying to reach.

 I would bet that those two are IPs or at the very least the last one! :)
 If you can, listing the HSDir fp, the IPs fp and the RP fp would be useful
 so we can learn if those fingerprints that are both in two circuits of 5
 hops are related to any entity of the HS dance. (I can help you with a
 patch to log those if you want.)

 {{{
 $1F4105C688E835A56AF3D66C787677B57240FFA2(open)
 $D7316BF7FD633DD7474B18C33E1D5FDEB04D26A7(open)
 }}}

 I bet you are right with this race here! Some circuit state could be wrong
 or updated to late. Figuring out if those two last hops are related to IPs
 would be very useful to narrow down our search.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21084#comment:6>
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