I cannot reproduce this. I am using Darwin 15.5.0 instead of 15.6.0, but the compiler is identical. I am using MPICH Git master from June 29. At this point, it is unclear to me if the bug is in MPICH or Clang. Jeff vsanthan-mobl1:BUGS jrhammon$ /opt/mpich/dev/clang/default/bin/mpichversion MPICH Version: 3.2 MPICH Release date: unreleased development copy MPICH Device: ch3:nemesis MPICH configure: CC=clang CXX=clang++ FC=false F77=false --enable-cxx --disable-fortran --with-pm=hydra --prefix=/opt/mpich/dev/clang/default --enable-cxx --enable-wrapper-rpath --disable-static --enable-shared MPICH CC: clang -O2 MPICH CXX: clang++ -O2 MPICH F77: false MPICH FC: false vsanthan-mobl1:BUGS jrhammon$ /opt/mpich/dev/clang/default/bin/mpicc -v mpicc for MPICH version 3.2 Apple LLVM version 7.3.0 (clang-703.0.31) Target: x86_64-apple-darwin15.5.0 Thread model: posix InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin clang: warning: argument unused during compilation: '-I /opt/mpich/dev/clang/default/include' On Tue, Jul 26, 2016 at 8:17 AM, Andreas Noack <[email protected]

wrote:

On my El Capitan macbook I get a segfault when running the program below with more than a single process but only when MPICH has been compiled with Clang.

I don't get that good debug info but here is some of what I got

(lldb) c Process 61129 resuming Process 61129 stopped * thread #1: tid = 0x32c438, 0x00000003119d0432 libpmpi.12.dylib`MPID_Request_create + 244, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT) frame #0: 0x00000003119d0432 libpmpi.12.dylib`MPID_Request_create + 244 libpmpi.12.dylib`MPID_Request_create: -> 0x3119d0432 <+244>: movaps %xmm0, 0x230(%rax) 0x3119d0439 <+251>: movq $0x0, 0x240(%rax) 0x3119d0444 <+262>: movl %ecx, 0x210(%rax) 0x3119d044a <+268>: popq %rbp

My version of Clang is

Apple LLVM version 7.3.0 (clang-703.0.31) Target: x86_64-apple-darwin15.6.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/usr/bin

and the bug has been confirmed by my colleague who is running Linux and compiling with Clang 3.8. The program runs fine with OpenMPI+Clang.

#include <mpi.h> #include <stdio.h> #include <stdlib.h>

int main(int argc, char *argv[]) { MPI_Init(&argc, &argv);

MPI_Comm comm = MPI_COMM_WORLD; uint64_t *A, *C; int rnk;

MPI_Comm_rank(comm, &rnk); A = calloc(1, sizeof(uint64_t)); C = calloc(2, sizeof(uint64_t)); A[0] = rnk + 1;

MPI_Allgather(A, 1, MPI_UINT64_T, C, 1, MPI_UINT64_T, comm);

MPI_Finalize(); return 0; }

Best regards

Andreas Noack Postdoctoral Associate Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology

_______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

-- Jeff Hammond [email protected] http://jeffhammond.github.io/ _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss