[tor-bugs] #21312 [Obfuscation/Snowflake]: snowflake-client is pegged at 100% cpu

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#21312: snowflake-client is pegged at 100% cpu
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 Reporter:  arlolra                |          Owner:  arlolra
     Type:  defect                 |         Status:  needs_review
 Priority:  High                   |      Milestone:
Component:  Obfuscation/Snowflake  |        Version:
 Severity:  Major                  |     Resolution:
 Keywords:                         |  Actual Points:
Parent ID:                         |         Points:
 Reviewer:                         |        Sponsor:
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Comment (by arlolra):

 > I'm guessing that this only narrows the race window, doesn't eliminate
 it completely, because setting a pointer to `nil` and testing it against
 `nil` are probably not atomic. Maybe we'll have to introduce some
 synchronization.

 Yup, I can bang that out if you'd like.

 > I suppose that the corresponding patches for client and proxy-go will
 also have the same flaw?

 The client already `nil`s the transport.

 > Perhaps this is the cause of the short delays that cypherpunks saw in
 comment:26: the proxy-go instances are randomly crashing and being
 restarted. I'll add some logging to them and see if that's the case.

 Probably, looks like the proxy code has the same pattern.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21312#comment:35>
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