sporadic segfault when not using MPI_THREAD_MULTIPLE #16
Description
Reproducer
https://github.com/ye-luo/gpu_shmem/tree/main/ishmem
In app.cpp, if the MPI initialization is changed from MPI_THREAD_MULTIPLE to
MPI_Init_thread(MPI_THREAD_FUNNELED)
MPI_Init()
I got segfault.
On Aurora/Sunspot with oneapi SDK 2025.3.1
$ mkdir build && cd build
$ cmake -DCMAKE_CXX_COMPILER=icpx -DCMAKE_CXX_FLAGS="-fiopenmp -fopenmp-targets=spir64" ..
$ make -j32
$ mpiexec -np 2 gpu_tile_compact.sh ./my_ishmem_app
x1921c1s0b0n0-hsn0.hsn.cm.sunspot.alcf.anl.gov: rank 9 died from signal 11
x1921c1s0b0n0-hsn0.hsn.cm.sunspot.alcf.anl.gov: rank 5 died from signal 15
Most applications actually don't use MPI_THREAD_MULTIPLE and requiring it significantly restrict the adoption of intel shmem.