[tor-bugs] #10804 [Tor Launcher]: Tor Launcher extension hangs periodically when Tor Browser is started

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#10804: Tor Launcher extension hangs periodically when Tor Browser is started
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     Reporter:            |      Owner:  brade
  trlaunch01              |     Status:  new
         Type:  defect    |  Milestone:
     Priority:  major     |    Version:
    Component:  Tor       |   Keywords:  tor launcher, TorBrowserTeam201410
  Launcher                |  Parent ID:
   Resolution:            |
Actual Points:            |
       Points:            |
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Comment (by mcs):

 Replying to [comment:17 cypherpunks]:
 > More likely two different bugs in here, hang in `readBytes()` of Tor
 Launcher long before progress completes, and hang triggered by
 `torbutton_local_tor_check` of Torbutton just after progress completes and
 before browser window should to appear. You can to reproduce it, place
 `while(true){}` loop to begin of `torbutton_send_ctrl_cmd` and observe the
 same as described behavior.

 Thanks cypherpunks.  You may be correct about there being two different
 hangs, but I am most suspicious of the interaction between HTTPS
 Everywhere's check.t.o connection (see ticket:9693#comment:5) and the
 torbutton_local_tor_check().

 Unfortunately, I have only been able to very very very rarely reproduce a
 hang (and only when I have been unprepared to debug it).  Adding a
 while(true) loop inside torbutton_send_ctrl_cmd() causes what appears to
 be a hang, but if I change it to a "for (var i = 0; i < 1000; ++i)" loop,
 then normal startup finishes after the for loop is done.  So that is not a
 true deadlock situation.

 Gravitas -- thank you for all of your debugging in #13072.  Can you try an
 experiment?  Use about:config to toggle
 extensions.torbutton.local_tor_check to false and also set
 extensions.torbutton.test_url to an empty string.  Modifying those two
 prefs will effectively disable all checks done by Torbutton.  I'd like to
 know if doing this eliminates the hang.

 Separately, you could also experiment by commenting out this line in HTTPS
 Everywhere:
    this.testProxySettings();
 (inside [https://gitweb.torproject.org/https-
 everywhere.git/blob/HEAD:/src/components/ssl-observatory.js#l145 ssl-
 observatory.js]).

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/10804#comment:18>
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