Hi All, I am having a consistent issue when using mpich with petsc. When calling another external library (mkl's pardiso), I will get the following assertion failure: Assertion failed in file src/binding/c/c_binding.c at line 29448: ((*comm)&(0x03ffffff)) < MPIR_COMM_N_BUILTIN I'm not really too sure why, if I turn assertions off in mpich, the program will seg fault later on. Stack trace for this looks like this: Assertion failed in file src/binding/c/c_binding.c at line 29448: ((*comm)&(0x03ffffff)) < MPIR_COMM_N_BUILTIN resfrac73bfaea(+0x1e992e0) [0x55b9357d52e0] resfrac73bfaea(+0x1e07ca8) [0x55b935743ca8] resfrac73bfaea(PMPI_Comm_free+0x580) [0x55b935642570] resfrac73bfaea(MKLMPI_Comm_free+0x38) [0x55b9385830f8] resfrac73bfaea(mkl_pds_lp64_reduce_rhs_real+0x4aa) [0x55b938edc2aa] resfrac73bfaea(mkl_pds_lp64_slv_omp_real+0x1c46) [0x55b93869a4c6] resfrac73bfaea(mkl_pds_lp64_solve_slave+0xd84) [0x55b935ba8514] resfrac73bfaea(mkl_pds_lp64_cluster_sparse_solver+0xec4) [0x55b935ba4b74] resfrac73bfaea(+0xdef3de) [0x55b93472b3de] resfrac73bfaea(MatSolve+0x521) [0x55b9349f17ef] resfrac73bfaea(+0x1a29db7) [0x55b935365db7] resfrac73bfaea(PCApply+0x73c) [0x55b934c53065] resfrac73bfaea(+0x19ee12d) [0x55b93532a12d] resfrac73bfaea(+0x115a74c) [0x55b934a9674c] resfrac73bfaea(KSPSolve+0x1b) [0x55b934a98d04] resfrac73bfaea(_ZN11nextstim_ns18PetscSolveParallelERNS_17SystemOfEquationsE+0x28b7) [0x55b934046767] resfrac73bfaea(_ZN11nextstim_ns21SlavePoolWaitAndSolveEv+0x5c7) [0x55b9341d5037] resfrac73bfaea(main+0x5db) [0x55b933eb292b] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7f14c99d5d90] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f14c99d5e40] resfrac73bfaea(_start+0x25) [0x55b933ecb0d5] The mpich configuration and version that we're using: MPICH Version: 4.3.0 MPICH Release date: Mon Feb 3 09:09:47 AM CST 2025 MPICH ABI: 17:0:5 MPICH Device: ch3:sock MPICH configure: --prefix=/opt/anl/petsc-3.23.2 MAKE=/usr/bin/make --libdir=/opt/anl/petsc-3.23.2/lib CC=gcc CFLAGS=-fPIC -Wno-lto-type-mismatch -Wno-stringop-overflow -O0 AR=/usr/bin/ar ARFLAGS=cr CXX=g++ CXXFLAGS=-Wno-lto-type-mismatch -Wno-psabi -O0 -std=gnu++20 FFLAGS=-ffree-line-length-none -ffree-line-length-0 -Wno-lto-type-mismatch -O0 -fallow-argument-mismatch FC=gfortran F77=gfortran FCFLAGS=-ffree-line-length-none -ffree-line-length-0 -Wno-lto-type-mismatch -O0 -fallow-argument-mismatch --disable-shared --with-pm=hydra --disable-java --with-hwloc=embedded --enable-fast=no --enable-error-messages=all --with-device=ch3:sock --enable-g=meminit,dbg PYTHON=/opt/intel/oneapi/intelpython/python3.12/bin/python3 --disable-maintainer-mode --disable-dependency-tracking MPICH CC: gcc -fPIC -Wno-lto-type-mismatch -Wno-stringop-overflow -O0 -g -O0 MPICH CXX: g++ -Wno-lto-type-mismatch -Wno-psabi -O0 -std=gnu++20 -g -O0 MPICH F77: gfortran -ffree-line-length-none -ffree-line-length-0 -Wno-lto-type-mismatch -O0 -fallow-argument-mismatch -g -O0 MPICH FC: gfortran -ffree-line-length-none -ffree-line-length-0 -Wno-lto-type-mismatch -O0 -fallow-argument-mismatch -g -O0 Any information or help on this would be greatly appreciated. *Chris Hewson* Senior Reservoir Simulation Engineer ResFrac +1.587.575.9792