SUMMARY
Several libpmemobj-cpp (https://github.com/pmem/libpmemobj-cpp) tests fail under drd with a following message:

411: ==3074519== Thread 2:
411: ==3074519== condition variable has not been initialized: cond 0x1fff000298
411: ==3074519==    at 0x4847048: pthread_cond_signal_intercept (drd_pthread_intercepts.c:1148)
411: ==3074519==    by 0x4847048: pthread_cond_signal@* (drd_pthread_intercepts.c:1161)
411: ==3074519==    by 0x48401CD: vgDrd_sema_up (drd_pthread_intercepts.c:297)
411: ==3074519==    by 0x48401CD: vgDrd_thread_wrapper (drd_pthread_intercepts.c:447)
411: ==3074519==    by 0x48B83F8: start_thread (in /usr/lib64/libpthread-2.32.9000.so)
411: ==3074519==    by 0x4BF8B42: clone (in /usr/lib64/libc-2.32.9000.so)

This error occurs even in tests which do not use conditional variable (only spawn some number of threads). It would seem that DRD reports an error on it's own conditional variable (?).

STEPS TO REPRODUCE (I was not able to provide a simple, standalone reproduction)
1. Run libpmemobj-cpp test suite (drd tests). Tests which are known to fail:
enumerable_thread_specific_iterators_0_drd, enumerable_thread_specific_size_0_drd, enumerable_thread_specific_access_0_drd

OBSERVED RESULT
Tests fail randomly, with an error message provided above.

EXPECTED RESULT
No errors.

SOFTWARE/OS VERSIONS
The error was found on fedora-33 and fedora-rawhide with valgrind-3.15.0 and valgrind-3.16.1

ADDITIONAL INFORMATION
Log from a failed build: https://kojipkgs.fedoraproject.org//work/tasks/5285/50625285/build.log