[petsc-dev] MPICH from --download-mpich reports inconsistent allocs/frees with valgrind

[Smith, Barry F.]

  Bug report to MPICH.

> On Jul 22, 2019, at 1:22 PM, Balay, Satish via petsc-dev <petsc-dev at mcs.anl.gov> wrote:
> 
> Hm - I don't think we were monitoring the leaks via valgrind that closely.
> 
> Looking at my old mpich install - I don't see a problem - so likely
> its an issue with newer versions of mpich.
> 
> Satish
> 
> -------
> balay at sb /home/balay/tmp
> $ mpichversion 
> MPICH Version:    	3.3
> MPICH Release date:	Wed Nov 21 11:32:40 CST 2018
> MPICH Device:    	ch3:sock
> MPICH configure: 	--prefix=/home/balay/soft/mpich-3.3 MAKE=/usr/bin/gmake --libdir=/home/balay/soft/mpich-3.3/lib CC=gcc CFLAGS=-fPIC -g -O AR=/usr/bin/ar ARFLAGS=cr CXX=g++ CXXFLAGS=-g -O -fPIC F77=gfortran FFLAGS=-fPIC -g -O FC=gfortran FCFLAGS=-fPIC -g -O --enable-shared --with-device=ch3:sock --with-pm=hydra --enable-fast=no --enable-error-messages=all --enable-g=meminit
> MPICH CC: 	gcc -fPIC -g -O   -O0
> MPICH CXX: 	g++ -g -O -fPIC  -O0
> MPICH F77: 	gfortran -fPIC -g -O  -O0
> MPICH FC: 	gfortran -fPIC -g -O  -O0
> MPICH Custom Information: 	
> balay at sb /home/balay/tmp
> $ printf "#include<mpi.h>\nint main(int a,char**b){MPI_Init(&a,&b);MPI_Finalize();}" > t.c && mpicc t.c && valgrind ./a.out
> ==9024== Memcheck, a memory error detector
> ==9024== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
> ==9024== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
> ==9024== Command: ./a.out
> ==9024== 
> ==9024== 
> ==9024== HEAP SUMMARY:
> ==9024==     in use at exit: 0 bytes in 0 blocks
> ==9024==   total heap usage: 1,886 allocs, 1,886 frees, 4,884,751 bytes allocated
> ==9024== 
> ==9024== All heap blocks were freed -- no leaks are possible
> ==9024== 
> ==9024== For lists of detected and suppressed errors, rerun with: -s
> ==9024== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
> balay at sb /home/balay/tmp
> 
> 
> 
> On Mon, 22 Jul 2019, Patrick Sanan via petsc-dev wrote:
> 
>> It was pointed out to me that valgrind memcheck reports inconsistent heap
>> usage information when running PETSc examples. All blocks are reported
>> freed, yet the number of allocations and frees are different. My guess as
>> to what's going on is that this is an MPICH issue, as I can reproduce the
>> behavior with a minimal MPI program.
>> 
>>> From the PETSc perspective, is this a known issue?  I'm wondering if this
>> inconsistency was always there, whether it's worth looking into more, etc.
>> 
>> Here's a 1-liner to reproduce, using a PETSc master build with
>> --download-mpich (though note that this doesn't use anything from PETSc
>> except the MPICH it builds for you).
>> 
>>     printf "#include<mpi.h>\nint main(int a,char
>> **b){MPI_Init(&a,&b);MPI_Finalize();}" > t.c &&
>> $PETSC_DIR/$PETSC_ARCH/bin/mpicc t.c && valgrind ./a.out
>> 
>> ==14242== Memcheck, a memory error detector
>> ==14242== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
>> ==14242== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
>> ==14242== Command: ./a.out
>> ==14242==
>> ==14242==
>> ==14242== HEAP SUMMARY:
>> ==14242==     in use at exit: 0 bytes in 0 blocks
>> ==14242==   total heap usage: *1,979 allocs, 1,974 frees*, 4,720,483 bytes
>> allocated
>> ==14242==
>> ==14242== All heap blocks were freed -- no leaks are possible
>> ==14242==
>> ==14242== For counts of detected and suppressed errors, rerun with: -v
>> ==14242== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
>> 
>