strange bug in combination with malloc_count

[LukasNalbach]

I am not sure where the root of this issue lies, but on some operating systems, a strange bug occurs when using libsais with OpenMP enabled in combination with malloc_count (https://github.com/bingmann/malloc_count) and gcc. I have not encountered any issues when using malloc_count in combination with any other library yet, so I suspected the issue might be linked to libsais and decided to post it here. I prepared a repository to illustrate it: https://github.com/LukasNalbach/libsais-malloc_count-bug

test-1.cpp uses malloc_count and libsais:
test-2.cpp uses libsais without malloc_count and test-3.cpp uses malloc_count without libsais, no errors.

The bug does not occur when using clang. It also occurs in the sigle-thread version, as long as LIBSAIS_USE_OPENMP is set to ON. It seems to occurr regardless of the gcc and OpenMP versions used. For example, on Ubuntu 18.04 and 22.04 the bug occurs, but on 20.04 and 23.04 it does not. The issue does not occur when executing the program with valgrind with the options --tool=memcheck --leak-check=full.

Even just linking against (not including or calling) libsais when also using malloc_count can cause the same issue in a simple "#pragma omp parallel for" region, regardless of whether LIBSAIS_USE_OPENMP is set to ON. I have not been able to replicate this issue in the example repository, but for example, it occurs here: https://github.com/LukasNalbach/move-r/blob/b615972ca07ea4031416b7450bea65c762cc9e7d/include/move_r/algorithms/construction/modes/common.cpp#L12

edit: Setting THREAD_SAFE_GCC_INTRINSICS to 1 does not solve the issue.

[IlyaGrebnov]

From description it looks like an issue with GCC specific implementation of Open MP runtime. I am also not sure why it only suffuses with libsais.

[LukasNalbach]

I found the solution to the problem, although I still do not understand why it does not always occur. It has nothing to do with libsais and has been fixed in ByteHamster-etc/malloc_count@f23b8c5.