[tor-bugs] #32564 [Core Tor/Tor]: Assertion pol->magic failed

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#32564: Assertion pol->magic failed
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 Reporter:  Logforme                        |          Owner:  nickm
     Type:  defect                          |         Status:  assigned
 Priority:  High                            |      Milestone:  Tor:
                                            |  0.4.3.x-final
Component:  Core Tor/Tor                    |        Version:  Tor: 0.4.1.6
 Severity:  Normal                          |     Resolution:
 Keywords:  assert crash backport 043-must  |  Actual Points:
Parent ID:                                  |         Points:
 Reviewer:                                  |        Sponsor:
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Comment (by nickm):

 So, there is only one kind of `circuitmux_policy_circ_data_t` in 0.4.1.x,
 so we don't need to worry about the case where this is another kind of
 data.  The pointer here is either:

   * An invalid pointer that is not pointing to an ewma_policy_circ_data_t.
   * A stale pointer that used to point to an ewma_policy_circ_data_t which
 has been freed.
   * A pointer that points to an ewma_policy_circ_data_t which has gotten
 corrupt.

 But I can't find plausible vectors for any of these things to happen.
 Because of the infrequency of this bug, I am almost tempted to suspect
 faulty memory, but that should always be a last-resort hypothesis.

 The best I can figure out here right now is to add a diagnostic patch.
 I'll open a child ticket.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32564#comment:6>
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