[tor-bugs] #21362 [Core Tor/Tor]: Intermittent crash when selected guard lacks a descriptor or routerstatus

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#21362: Intermittent crash when selected guard lacks a descriptor or routerstatus
------------------------------+-----------------------------------
     Reporter:  teor          |      Owner:
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:  Tor: 0.3.0.x-final
    Component:  Core Tor/Tor  |    Version:  Tor: 0.3.0.2-alpha
     Severity:  Major         |   Keywords:  crash guard tor-relay
Actual Points:                |  Parent ID:
       Points:  1             |   Reviewer:
      Sponsor:                |
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 I see this crash when running make test-network-all with the latest
 master:

 {{{
 Feb 01 16:53:22.000 [info] choose_good_exit_server_general(): Chose exit
 server '$65B77ACB2E202F610D3D7D12CA7BA1269C945DEB~test002r at 127.0.0.1'
 Feb 01 16:53:22.000 [debug] extend_info_from_node(): using 127.0.0.1:5002
 for test002r
 Feb 01 16:53:22.000 [info] extend_info_from_node(): Including Ed25519 ID
 for $65B77ACB2E202F610D3D7D12CA7BA1269C945DEB~test002r at 127.0.0.1
 Feb 01 16:53:22.000 [debug] onion_extend_cpath(): Path is 0 long; we want
 3
 Feb 01 16:53:22.000 [info] select_entry_guard_for_circuit(): Selected
 primary guard test000a ($02C177E1A8001A62F9476B8BCFC80B6A7F45AFB8) for
 circuit.
 Feb 01 16:53:22.000 [err] tor_assertion_failed_(): Bug:
 src/or/circuitbuild.c:2372: onion_extend_cpath: Assertion info || client
 failed; aborting. (on Tor 0.3.0.2-alpha-dev 6dd7e66019e9aa53)
 Feb 01 16:53:22.000 [err] Bug: Assertion info || client failed in
 onion_extend_cpath at src/or/circuitbuild.c:2372. Stack trace: (on Tor
 0.3.0.2-alpha-dev 6dd7e66019e9aa53)
 Feb 01 16:53:22.000 [err] Bug:     0   tor
 0x000000010872ad34 log_backtrace + 68 (on Tor 0.3.0.2-alpha-dev
 6dd7e66019e9aa53)
 }}}

 It appears that this check in extend_info_from_node is failing:
 {{{
   if (node->ri == NULL && (node->rs == NULL || node->md == NULL))
     return NULL;
 }}}

 We really shouldn't be selecting a guard unless it passes this test.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21362>
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