[tor-bugs] #31524 [Core Tor/Tor]: GETINFO bw-event-cache spike value(s) in it

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#31524: GETINFO bw-event-cache  spike value(s) in it
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 Reporter:  toralf                    |          Owner:  (none)
     Type:  defect                    |         Status:  new
 Priority:  Medium                    |      Milestone:  Tor: 0.4.2.x-final
Component:  Core Tor/Tor              |        Version:  Tor: 0.4.1.4-rc
 Severity:  Normal                    |     Resolution:
 Keywords:  042-should, security-low  |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Changes (by teor):

 * status:  needs_information => new


Comment:

 If we can't reproduce these issues on older Tor versions, that makes it
 hardrr for us to diagnose this issue,

 Here's how I think we can move forward:
 * set an "unreasonably large" bandwidth amount threshold, and log a BUG()
 warning when:
   * we try to add an amount over that threshold,
   * any of our totals are over that threshold, or
   * we try to put an amount over that threshold in our descriptor, extra-
 info, or control port.
 * when we subtract a bandwidth value, log a BUG() if the final amount
 would be less than zero.

 (We recently added code that subtracts bandwidth values if the circuit is
 closed before writing.)

 BUG() warnings log stack traces, so we should be able to locate the source
 of the issue more easily.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31524#comment:3>
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