Hi, I’m trying to debug a GPU-aware runtime for the Global Arrays library. We had a version of this working a while ago, but it has mysteriously started failing and we are trying to track down why. Currently, we are getting failures in MPI_Wait and were wondering if anyone could provide some information on what exactly seems to be failing inside the wait call. The error we are getting is Abort(206752655) on node 0: Fatal error in internal_Wait: Other MPI error, error stack: internal_Wait(68205)..........: MPI_Wait(request=0x500847a0, status=0x7ffff9331800) failed MPIR_Wait(780)................: MPIR_Wait_state(737)..........: MPIDI_progress_test(134)......: MPIDI_OFI_handle_cq_error(793): OFI poll failed (ofi_events.c:793:MPIDI_OFI_handle_cq_error:Input/output error) I’ve verified that the handle corresponding to 0x500847a0 is getting set earlier in the code in an MPI_Isend call and that no MPI_Wait or MPI_Test is called on the handle before it crashes with the above error message. I’m using MPICH 4.2.1 using gcc/8.3.0. The MPICH library was configured with ../configure --prefix=/people/d3g293/mpich/mpich-4.2.1/build_newell/install \ --with-device=ch4:ofi:sockets --with-libfabric=embedded \ --without-ucx --enable-threads=multiple --with-slurm \ CC=gcc CXX=g+ I’ve tried building with UCX and gotten the same results. Are these errors indicative of corruption of the request handle or problems with some internal MPI data structures or something else? Any information you can provide would be appreciated. Thanks, Bruce