[tor-bugs] #27813 [Core Tor/Tor]: Tor 0.3.4.8 is leaking memory

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#27813: Tor 0.3.4.8 is leaking memory
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 Reporter:  anong                                |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  needs_information
 Priority:  Very High                            |      Milestone:  Tor:
                                                 |  0.3.5.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.3.4.8
 Severity:  Critical                             |     Resolution:
 Keywords:  regression? memleak oom              |  Actual Points:
  034-backport tor-relay 035-must                |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
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Comment (by starlight):

 Replying to [comment:30 dgoulet]:
 >. . .
 >KIST should prevent that in theory but not entirely. Some could always go
 as in flushing 1M of cells and only one goes through leaving the rest in
 the kernel.
 >
 >The bigger issue is that we still have cells bypassing the KIST scheduler
 that are directly written on the socket. We have several ticket open about
 these issues.

 Thank you for the update, the details are informative and interesting.

 After posting I realized stuck sockets will hide an EOF condition and when
 the other side closes EOFs are not detected resulting in a socket leak,
 but one cured by the fix.  A more carefully read turns up that performance
 degradation did result.

 Newer kernels account kernel SKBs under the owning process for correct
 CGROUP resource control, and graphs above show the leaked memory as "app"
 memory.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27813#comment:31>
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