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Re: [tor-bugs] #15901 [Tor]: apparent memory corruption -- very difficult to isolate

#15901: apparent memory corruption -- very difficult to isolate
---------------------------+--------------------------------
     Reporter:  starlight  |      Owner:
         Type:  defect     |     Status:  new
     Priority:  critical   |  Milestone:  Tor: 0.2.7.x-final
    Component:  Tor        |    Version:  Tor: 0.2.5.12
   Resolution:             |   Keywords:
Actual Points:             |  Parent ID:
       Points:             |
---------------------------+--------------------------------

Comment (by starlight):

 zero chance it would run live with Valgrind,
 which is about 20x

 I've used memory checkers for years and
 Google's ASAN is genius--2x for most
 code and happily the multiplier for
 tor is more like 1.3, at least for
 steady traffic; circuit setup is probably
 more like 2x or 3x (when openssl is
 instrumented)

 Adding UBSAN this time did not appear to
 make much difference to CPU and with
 luck it will catch it

 worst case I'm planning to pick up
 a SkyLake later this year for which
 gcc 5.1 supports MPX in UBSAN
 --this hardware memory checking
 feature can catch intra-structure
 boundary violations, something
 ASAN presently does not detect

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15901#comment:15>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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