MemorySanitizer: use-of-uninitialized-value

[agauniyal]

==17342==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x5599d1e7d337 in std::_Rb_tree<doctest::detail::TestCase, doctest::detail::TestCase, std::_Identity<doctest::detail::TestCase>, std::less<doctest::detail::TestCase>, std::allocator<doctest::detail::TestCase> >::_M_get_insert_unique_pos(doctest::detail::TestCase const&) /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.2.1/../../../../include/c++/7.2.1/bits/stl_tree.h:2035:7
    #1 0x5599d1e7cc2b in std::pair<std::_Rb_tree_iterator<doctest::detail::TestCase>, bool> std::_Rb_tree<doctest::detail::TestCase, doctest::detail::TestCase, std::_Identity<doctest::detail::TestCase>, std::less<doctest::detail::TestCase>, std::allocator<doctest::detail::TestCase> >::_M_insert_unique<doctest::detail::TestCase const&>(doctest::detail::TestCase const&) /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.2.1/../../../../include/c++/7.2.1/bits/stl_tree.h:2091:4
    #2 0x5599d1e340b4 in std::set<doctest::detail::TestCase, std::less<doctest::detail::TestCase>, std::allocator<doctest::detail::TestCase> >::insert(doctest::detail::TestCase const&) /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.2.1/../../../../include/c++/7.2.1/bits/stl_set.h:502:9
    #3 0x5599d1de40aa in doctest::detail::regTest(doctest::detail::TestCase const&) /home/agauniyal/.conan/data/doctest/1.2.6/bincrafters/stable/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/include/doctest.h:4185:30
    #4 0x5599d1d5a480 in __cxx_global_var_init.309 /home/agauniyal/projects/termdb/build/../test/test.cpp:17:1
    #5 0x5599d1d5bc87 in _GLOBAL__sub_I_test.cpp /home/agauniyal/projects/termdb/build/../test/test.cpp
    #6 0x5599d1eacaac in __libc_csu_init (/home/agauniyal/projects/termdb/build/test/mainTest+0x170aac)
    #7 0x7fa862b16eda in __libc_start_main (/usr/lib/libc.so.6+0x20eda)
    #8 0x5599d1d5bce9 in _start (/home/agauniyal/projects/termdb/build/test/mainTest+0x1fce9)

SUMMARY: MemorySanitizer: use-of-uninitialized-value /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/7.2.1/../../../../include/c++/7.2.1/bits/stl_tree.h:2035:7 in std::_Rb_tree<doctest::detail::TestCase, doctest::detail::TestCase, std::_Identity<doctest::detail::TestCase>, std::less<doctest::detail::TestCase>, std::allocator<doctest::detail::TestCase> >::_M_get_insert_unique_pos(doctest::detail::TestCase const&)
Exiting

[agauniyal]

This could be a false positive too.

[onqtam]

are you using an instrumented version of the stdlib? I think that's the way to go with the memory sanitizer (unlike other sanitizers like the address/ub/thread ones) - especially since the error is somewhere in the stl container...

But if you are using an instrumented stdlib and given that the sanitizers don't give false positives I'd be curious to see a complete example that reproduces this - perhaps some test suites and decorators are in play...? I double-checked the code and it seems fine

[agauniyal]

I apologize, somehow I missed building the instrumented version of stdlib. This must be a false positive then :)