Hello there, I'm Pedro, and I work in a research group that researches the use of OpenMP in distributed systems using MPI as a communication layer. In particular, we are working with multithreaded MPICH, where there are two main "users" of MPI in our system, an Event System and a Fault Tolerance (FT) system that work together in separate threads. Those systems carry mainly MPI asynchronous messages where the requests were freed or tested until the completion. Everything works fine and correctly. Recently, sometimes we are getting an assert error in the program ending when calling MPI_Finalize(), here is the error with some callstack: (*An important note: this error does not always happen. In fact, it is much more common for the application to finish correctly, instead of asserting like that*) *Error in system call pthread_mutex_destroy: Device or resource busy src/mpi/init/mutex.c:90Assertion failed in file src/mpi/init/mutex.c at line 91: err == 0/usr/local/mpi/lib/libmpi.so.12(MPL_backtrace_show+0x35) [0x7f3429505673]/usr/local/mpi/lib/libmpi.so.12(+0x3248b4) [0x7f34294a38b4]/usr/local/mpi/lib/libmpi.so.12(MPI_Finalize+0xb8) [0x7f34293a4b28]/builds/ompcluster/llvm-project/build/projects/openmp/libomptarget/libomptarget.rtl.mpi.so <http://libomptarget.rtl.mpi.so>(+0xafa5) [0x7f342b800fa5]/lib/x86_64-linux-gnu/libc.so.6(+0x43161) [0x7f342a849161]/lib/x86_64-linux-gnu/libc.so.6(+0x4325a) [0x7f342a84925a]/builds/ompcluster/llvm-project/build/projects/openmp/libomptarget/libomptarget.rtl.mpi.so <http://libomptarget.rtl.mpi.so>(+0xf3d9) [0x7f342b8053d9]/builds/ompcluster/llvm-project/build/projects/openmp/libomptarget/libomptarget.so.12(__tgt_register_lib+0xf9) [0x7f342b8673c9]./ompcluster/main() [0x40ef3d]/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x78) [0x7f342a827b88]./ompcluster/main() [0x402a5a]Abort(1) on node 2: Internal error* I've looked at the mutex.c file and saw that this is a problem when destroying the global mutex employed in the multithread MPI. I would like to ask if there are any known scenarios, or common reasons for this problem to occur, to help me find what could be happening at the end of the execution. Here is the MPICH configuration in our container: *$ mpichversion* *MPICH Version: 3.4.2MPICH Release date: Wed May 26 15:51:40 CDT 2021MPICH Device: ch4:ucxMPICH configure: --prefix=/usr/local/mpi --disable-static --with-device=ch4:ucx --with-ucx=/usr/local/ucxMPICH CC: gcc -O2MPICH CXX: g++ -O2MPICH F77: gfortran -O2MPICH FC: gfortran -O2MPICH Custom Information: * Regards, Pedro