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

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#21312: snowflake-client is pegged at 100% cpu
-----------------------------------+------------------------------
 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:
-----------------------------------+------------------------------

Comment (by dcf):

 Replying to [comment:55 dcf]:
 > I've started some proxy-go instances with the patches. The one on my
 desktop has seen a few opens and closes so far, and is still running. I'll
 make more graphs of restarts tomorrow, but so far it's looking good, one
 hour without any abnormal restarts.

  * The first blue line is [https://gitweb.torproject.org/pluggable-
 transports/snowflake.git/commit/?id=44ab82bc612dac3f9605afd44f057ef199b2cc12
 44ab82bc61], which just adds a "starting" marker to the log.
  * The second blue line is [https://gitweb.torproject.org/pluggable-
 transports/snowflake.git/commit/?id=f2abf5b60c289103d8661b8e54b3d3aee43a4aaf
 f2abf5b60c], which tries to protect against the crash with a `nil` check.
  * The third blue line is comment:54, which adds synchonization around
 datachannels and peerconnections.

 The patches from comment:54 have stopped the frequent crashes. Now the
 process is restarting according to schedule.

 [[Image(proxy-go-starting.20180316.png)]]

 Here are the fd and memory graphs. Now we see memory slowly increasing
 over time--hard to say at this point whether it's just normal elevated
 usage or a leak. I'll leave the monitor running.

 [[Image(proxy-go-fd.20180316.png)]]

 [[Image(proxy-go-mem.20180316.png)]]

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21312#comment:57>
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