I think this is the same issue reported on the devel list yesterday. If it is, Daniel Ibanez provided a patch that I've merged into my (completely unofficial fork on github) and will push to the official MPICH review repo tonight.
Hi,
we upgraded from mpich 3.1.2 to 3.2 and our nightly builds under valgrind show a new valgrind warning, which I suppose originates from the mpi library, rather than our code (given the stack trace below and the fact that they are absent with 3.1):
There are two slightly distinct traces (alltoall and alltoallv):
==30165== Conditional jump or move depends on uninitialised value(s)
==30165== at 0x6E00056: MPIR_Process_status (mpiimpl.h:4394)
==30165== by 0x6E00056: MPIC_Waitall (helper_fns.c:774)
==30165== by 0x6D5A853: MPIR_Alltoall_intra (alltoall.c:369)
==30165== by 0x6D5B63C: MPIR_Alltoall (alltoall.c:564)
==30165== by 0x6D5B6EF: MPIR_Alltoall_impl (alltoall.c:599)
==30165== by 0x6D5BF07: PMPI_Alltoall (alltoall.c:722)
==30165== by 0x6AFF0DC: PMPI_ALLTOALL (alltoallf.c:276)
==30165== by 0x1D04699: __message_passing_MOD_mp_alltoall_i22
==30201== Conditional jump or move depends on uninitialised value(s)
==30201== at 0x6E00056: MPIR_Process_status (mpiimpl.h:4394)
==30201== by 0x6E00056: MPIC_Waitall (helper_fns.c:774)
==30201== by 0x6D5C4EA: MPIR_Alltoallv_intra (alltoallv.c:194)
==30201== by 0x6D5CEC9: MPIR_Alltoallv (alltoallv.c:339)
==30201== by 0x6D5CFAA: MPIR_Alltoallv_impl (alltoallv.c:376)
==30201== by 0x6D5D8CA: PMPI_Alltoallv (alltoallv.c:527)
==30201== by 0x6AFF13E: PMPI_ALLTOALLV (alltoallvf.c:276)
==30201== by 0x1CCE180: __message_passing_MOD_mp_alltoall_z22v (message_passing_z.f90:223)
Is this issue already known/fixed ?
I saw there was a somewhat related change (which is part of 3.2):
https://trac.mpich.org/projects/mpich/changeset/be7c17b3177ccb0ede49761b44a438952360b061
but maybe that change was not fully complete ?
Best regards,
Joost VandeVondele
Prof. Dr. Joost VandeVondele
Nanoscale Simulations
ETH Zurich
HIT G 41.4
Wolfgang-Pauli-Strasse 27
8093 Zurich, Switzerland
Joost.VandeVondele@mat.ethz.ch
http://www.nanosim.mat.ethz.ch/
Tel.: +41 (0)44 6338451