[tor-bugs] #24975 [Core Tor/Tor]: sched: scheduler_notify_networkstatus_changed() calls select_scheduler() without the new consensus

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#24975: sched: scheduler_notify_networkstatus_changed() calls select_scheduler()
without the new consensus
-------------------------------------+------------------------------------
 Reporter:  dgoulet                  |          Owner:  dgoulet
     Type:  defect                   |         Status:  assigned
 Priority:  High                     |      Milestone:  Tor: 0.3.3.x-final
Component:  Core Tor/Tor             |        Version:
 Severity:  Normal                   |     Resolution:
 Keywords:  032-backport, tor-sched  |  Actual Points:
Parent ID:                           |         Points:
 Reviewer:                           |        Sponsor:
-------------------------------------+------------------------------------

Comment (by arma):

 Quoting the oniongit comment here for ease of history:
 """
 When this function is called, the consensus ***has not yet changed***. It
 is still old_c. It will be new_c soon. This is your chance to take new
 actions.

 So if you ignore new_c and just call stuff that looks at "the consensus",
 you're going to be looking at the current consensus, i.e. old_c.

 I think this is a bug in 0.3.2 with
 scheduler_notify_networkstatus_changed() too, in that set_scheduler() can
 call select_scheduler() which calls scheduler_can_use_kist() which calls
 kist_scheduler_run_interval(NULL) -- so even though
 kist_scheduler_run_interval knows how to receive an ns as an argument, it
 doesn't get new_c here.
 """

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24975#comment:2>
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