[tor-bugs] #21788 [Core Tor/Tor]: Very small memory leak with --verify-config

[Tor Bug Tracker & Wiki]

#21788: Very small memory leak with --verify-config
------------------------------+------------------------------
     Reporter:  Jigsaw52      |      Owner:  Jigsaw52
         Type:  defect        |     Status:  new
     Priority:  Very Low      |  Milestone:
    Component:  Core Tor/Tor  |    Version:  Tor: unspecified
     Severity:  Trivial       |   Keywords:  memory leak
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
------------------------------+------------------------------
 When tor is run with the flag --verify-config, there is a memory leak of
 45 bytes. Although the leak is insignificant, not leaking any memory helps
 testing the configuration related code against memory leaks.

 This leak is due to clean_up_backtrace_handler not being called during tor
 shutdown process. I believe the fix is calling it inside tor_free_all. I
 will post a link to a branch with my proposed fix.

 Valgrind log:

 {{{
 user at lubuntu:~/Desktop/tor$ valgrind --tool=memcheck --leak-check=full
 --show-leak-kinds=all  /usr/local/bin/tor --verify-config
 ==19135== Memcheck, a memory error detector
 ==19135== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
 ==19135== Using Valgrind-3.12.0.SVN and LibVEX; rerun with -h for
 copyright info
 ==19135== Command: /usr/local/bin/tor --verify-config
 ==19135==
 Mar 20 00:59:33.916 [notice] Tor 0.3.1.0-alpha-dev (git-411736a13250586c)
 running on Linux with Libevent 2.0.21-stable, OpenSSL 1.0.2g and Zlib
 1.2.8.
 Mar 20 00:59:34.005 [notice] Tor can't help you if you use it wrong! Learn
 how to be safe at https://www.torproject.org/download/download#warning
 Mar 20 00:59:34.008 [notice] This version is not a stable Tor release.
 Expect more bugs than usual.
 Mar 20 00:59:34.036 [notice] Read configuration file
 "/usr/local/etc/tor/torrc".
 Configuration was valid
 ==19135==
 ==19135== HEAP SUMMARY:
 ==19135==     in use at exit: 45 bytes in 1 blocks
 ==19135==   total heap usage: 8,709 allocs, 8,708 frees, 460,735 bytes
 allocated
 ==19135==
 ==19135== 45 bytes in 1 blocks are still reachable in loss record 1 of 1
 ==19135==    at 0x4C2CB3F: malloc (in /usr/lib/valgrind
 /vgpreload_memcheck-amd64-linux.so)
 ==19135==    by 0x61CBB4F: __vasprintf_chk (vasprintf_chk.c:80)
 ==19135==    by 0x2669F3: vasprintf (stdio2.h:210)
 ==19135==    by 0x2669F3: tor_vasprintf (compat.c:539)
 ==19135==    by 0x2669F3: tor_asprintf (compat.c:516)
 ==19135==    by 0x2657E1: configure_backtrace_handler (backtrace.c:232)
 ==19135==    by 0x1556AF: tor_main (main.c:3609)
 ==19135==    by 0x14F238: main (tor_main.c:34)
 ==19135==
 ==19135== LEAK SUMMARY:
 ==19135==    definitely lost: 0 bytes in 0 blocks
 ==19135==    indirectly lost: 0 bytes in 0 blocks
 ==19135==      possibly lost: 0 bytes in 0 blocks
 ==19135==    still reachable: 45 bytes in 1 blocks
 ==19135==         suppressed: 0 bytes in 0 blocks
 ==19135==
 ==19135== For counts of detected and suppressed errors, rerun with: -v
 ==19135== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21788>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online