Invalid read problem

mpitest.cpp

// Compile and test with: mpicxx -std=c++11 -g -O0 mpitest.cpp  && LD_PRELOAD=/usr/lib/valgrind/libmpiwrap-amd64-linux.so mpirun -n 1 valgrind --read-var-info=yes --leak-check=full ./a.out

#include <vector>
#include <iostream>

#include <mpi.h>

using namespace std;

struct MPI_EventData
{
  int size;
};


void collect()
{
  // Register MPI datatype
  MPI_Datatype MPI_EVENTDATA;
  int blocklengths[] = {1};
  MPI_Aint displacements[] = {offsetof(MPI_EventData, size) };
  MPI_Datatype types[] = {MPI_INT};
  MPI_Type_create_struct(1, blocklengths, displacements, types, &MPI_EVENTDATA);
  MPI_Type_commit(&MPI_EVENTDATA);
 
  int rank, MPIsize;
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Comm_size(MPI_COMM_WORLD, &MPIsize);
  
  std::vector<MPI_Request> requests;
  std::vector<int> eventsPerRank(MPIsize);
  size_t eventsSize = 3; // each rank sends three events, invalid read happens only if eventsSize > 1
  MPI_Gather(&eventsSize, 1, MPI_INT, eventsPerRank.data(), 1, MPI_INT, 0, MPI_COMM_WORLD);

  std::vector<MPI_EventData> eventSendBuf; // Buffer to hold the MPI_EventData object
    
  for (int i = 0; i < eventsSize; ++i) {
    MPI_EventData eventdata;
    MPI_Request req;

    eventdata.size = 5;
    eventSendBuf.push_back(eventdata);

    cout << "Isending event " << i << endl;
    MPI_Isend(&eventSendBuf.back(), 1, MPI_EVENTDATA, 0, 0, MPI_COMM_WORLD, &req);
    requests.push_back(req);
  }
  
  if (rank == 0) {
    for (int i = 0; i < MPIsize; ++i) {
      for (int j = 0; j < eventsPerRank[i]; ++j) {
        MPI_EventData ev;
        MPI_Recv(&ev, 1, MPI_EVENTDATA, i, MPI_ANY_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
                              
        cout << "Received Size = " << ev.size << endl;        
      }
    }
  }    
  MPI_Waitall(requests.size(), requests.data(), MPI_STATUSES_IGNORE);
  MPI_Type_free(&MPI_EVENTDATA);
}


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

  collect();

  MPI_Finalize();
}


/*

 % mpicxx -std=c++11 -g -O0 mpitest.cpp  && LD_PRELOAD=/usr/lib/valgrind/libmpiwrap-amd64-linux.so mpirun -n 1 valgrind --read-var-info=yes --leak-check=full ./a.out
==13584== Memcheck, a memory error detector
==13584== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==13584== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==13584== Command: ./a.out
==13584== 
valgrind MPI wrappers 13584: Active for pid 13584
valgrind MPI wrappers 13584: Try MPIWRAP_DEBUG=help for possible options
==13584== Thread 3:
==13584== Syscall param epoll_pwait(sigmask) points to unaddressable byte(s)
==13584==    at 0x61A0FE6: epoll_pwait (in /usr/lib/libc-2.26.so)
==13584==    by 0x677CDDC: ??? (in /usr/lib/openmpi/libopen-pal.so.40.0.0)
==13584==    by 0x6780EDA: opal_libevent2022_event_base_loop (in /usr/lib/openmpi/libopen-pal.so.40.0.0)
==13584==    by 0x93100CE: ??? (in /usr/lib/openmpi/openmpi/mca_pmix_pmix2x.so)
==13584==    by 0x5E9408B: start_thread (in /usr/lib/libpthread-2.26.so)
==13584==    by 0x61A0E7E: clone (in /usr/lib/libc-2.26.so)
==13584==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==13584== 
Isending event 0
==13584== Thread 1:
==13584== Invalid read of size 2
==13584==    at 0x4C33B20: memmove (vg_replace_strmem.c:1258)
==13584==    by 0x11A7BB: MPI_EventData* std::__copy_move<true, true, std::random_access_iterator_tag>::__copy_m<MPI_EventData>(MPI_EventData const*, MPI_EventData const*, MPI_EventData*) (stl_algobase.h:368)
==13584==    by 0x11A70B: MPI_EventData* std::__copy_move_a<true, MPI_EventData*, MPI_EventData*>(MPI_EventData*, MPI_EventData*, MPI_EventData*) (stl_algobase.h:386)
==13584==    by 0x11A62B: MPI_EventData* std::__copy_move_a2<true, MPI_EventData*, MPI_EventData*>(MPI_EventData*, MPI_EventData*, MPI_EventData*) (stl_algobase.h:424)
==13584==    by 0x11A567: MPI_EventData* std::copy<std::move_iterator<MPI_EventData*>, MPI_EventData*>(std::move_iterator<MPI_EventData*>, std::move_iterator<MPI_EventData*>, MPI_EventData*) (stl_algobase.h:456)
==13584==    by 0x11A478: MPI_EventData* std::__uninitialized_copy<true>::__uninit_copy<std::move_iterator<MPI_EventData*>, MPI_EventData*>(std::move_iterator<MPI_EventData*>, std::move_iterator<MPI_EventData*>, MPI_EventData*) (stl_uninitialized.h:101)
==13584==    by 0x11A306: MPI_EventData* std::uninitialized_copy<std::move_iterator<MPI_EventData*>, MPI_EventData*>(std::move_iterator<MPI_EventData*>, std::move_iterator<MPI_EventData*>, MPI_EventData*) (stl_uninitialized.h:134)
==13584==    by 0x11A05B: MPI_EventData* std::__uninitialized_copy_a<std::move_iterator<MPI_EventData*>, MPI_EventData*, MPI_EventData>(std::move_iterator<MPI_EventData*>, std::move_iterator<MPI_EventData*>, MPI_EventData*, std::allocator<MPI_EventData>&) (stl_uninitialized.h:289)
==13584==    by 0x119AEC: MPI_EventData* std::__uninitialized_move_if_noexcept_a<MPI_EventData*, MPI_EventData*, std::allocator<MPI_EventData> >(MPI_EventData*, MPI_EventData*, MPI_EventData*, std::allocator<MPI_EventData>&) (stl_uninitialized.h:312)
==13584==    by 0x1190D2: void std::vector<MPI_EventData, std::allocator<MPI_EventData> >::_M_realloc_insert<MPI_EventData const&>(__gnu_cxx::__normal_iterator<MPI_EventData*, std::vector<MPI_EventData, std::allocator<MPI_EventData> > >, MPI_EventData const&) (vector.tcc:424)
==13584==    by 0x118B17: std::vector<MPI_EventData, std::allocator<MPI_EventData> >::push_back(MPI_EventData const&) (stl_vector.h:948)
==13584==    by 0x113B6E: collect() (mpitest.cpp:42)
==13584==  Address 0xd315ca0 is 0 bytes inside a block of size 4 alloc'd
==13584==    at 0x4C2D54F: operator new(unsigned long) (vg_replace_malloc.c:334)
==13584==    by 0x11A2BB: __gnu_cxx::new_allocator<MPI_EventData>::allocate(unsigned long, void const*) (new_allocator.h:111)
==13584==    by 0x119FE2: std::allocator_traits<std::allocator<MPI_EventData> >::allocate(std::allocator<MPI_EventData>&, unsigned long) (alloc_traits.h:436)
==13584==    by 0x119A87: std::_Vector_base<MPI_EventData, std::allocator<MPI_EventData> >::_M_allocate(unsigned long) (stl_vector.h:172)
==13584==    by 0x119055: void std::vector<MPI_EventData, std::allocator<MPI_EventData> >::_M_realloc_insert<MPI_EventData const&>(__gnu_cxx::__normal_iterator<MPI_EventData*, std::vector<MPI_EventData, std::allocator<MPI_EventData> > >, MPI_EventData const&) (vector.tcc:406)
==13584==    by 0x118B17: std::vector<MPI_EventData, std::allocator<MPI_EventData> >::push_back(MPI_EventData const&) (stl_vector.h:948)
==13584==    by 0x113B6E: collect() (mpitest.cpp:42)
==13584==    by 0x113DEE: main (mpitest.cpp:68)
==13584== 
Isending event 1
Isending event 2
Received Size = 5
Received Size = 5
Received Size = 5
==13584== 
==13584== HEAP SUMMARY:
==13584==     in use at exit: 1,898 bytes in 44 blocks
==13584==   total heap usage: 18,037 allocs, 17,993 frees, 4,086,090 bytes allocated
==13584==
==13584== 5 bytes in 1 blocks are definitely lost in loss record 1 of 44
==13584==    at 0x4C2CEDF: malloc (vg_replace_malloc.c:299)
==13584==    by 0x6130B9A: strdup (in /usr/lib/libc-2.26.so)
==13584==    by 0x954B720: ???
==13584==    by 0x9312913: ???
==13584==    by 0x9313114: ???
==13584==    by 0x930FE31: ???
==13584==    by 0x92CA3AD: ???
==13584==    by 0x92A3ED7: ???
==13584==    by 0x867C876: ???
==13584==    by 0x647BBEA: orte_init (in /usr/lib/openmpi/libopen-rte.so.40.0.0)
==13584==    by 0x52E3F77: ompi_mpi_init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==    by 0x530B78D: PMPI_Init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==
==13584== 12 bytes in 1 blocks are definitely lost in loss record 2 of 44
==13584==    at 0x4C2CEDF: malloc (vg_replace_malloc.c:299)
==13584==    by 0x6130B9A: strdup (in /usr/lib/libc-2.26.so)
==13584==    by 0x954FA92: ???
==13584==    by 0x9323720: ???
==13584==    by 0x92CA651: ???
==13584==    by 0x92A3ED7: ???
==13584==    by 0x867C876: ???
==13584==    by 0x647BBEA: orte_init (in /usr/lib/openmpi/libopen-rte.so.40.0.0)
==13584==    by 0x52E3F77: ompi_mpi_init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==    by 0x530B78D: PMPI_Init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==    by 0x4E4A2C0: PMPI_Init (libmpiwrap.c:2271)
==13584==    by 0x113DE9: main (mpitest.cpp:66)
==13584==
==13584== 35 bytes in 1 blocks are definitely lost in loss record 24 of 44
==13584==    at 0x4C2CEDF: malloc (vg_replace_malloc.c:299)
==13584==    by 0x6130B9A: strdup (in /usr/lib/libc-2.26.so)
==13584==    by 0x954B6B8: ???
==13584==    by 0x9312913: ???
==13584==    by 0x9313114: ???
==13584==    by 0x930FE31: ???
==13584==    by 0x92CA3AD: ???
==13584==    by 0x92A3ED7: ???
==13584==    by 0x867C876: ???
==13584==    by 0x647BBEA: orte_init (in /usr/lib/openmpi/libopen-rte.so.40.0.0)
==13584==    by 0x52E3F77: ompi_mpi_init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==    by 0x530B78D: PMPI_Init (in /usr/lib/openmpi/libmpi.so.40.0.0)
==13584==
==13584== 1,608 (320 direct, 1,288 indirect) bytes in 1 blocks are definitely lost in loss record 44 of 44
==13584==    at 0x4C2F0FF: realloc (vg_replace_malloc.c:785)
==13584==    by 0x92B1D7E: ???
==13584==    by 0x92B9FFE: ???
==13584==    by 0x92BB03E: ???
==13584==    by 0x6781AD8: opal_libevent2022_event_base_loop (in /usr/lib/openmpi/libopen-pal.so.40.0.0)
==13584==    by 0x93100CE: ???
==13584==    by 0x5E9408B: start_thread (in /usr/lib/libpthread-2.26.so)
==13584==    by 0x61A0E7E: clone (in /usr/lib/libc-2.26.so)
==13584==
==13584== LEAK SUMMARY:
==13584==    definitely lost: 372 bytes in 4 blocks
==13584==    indirectly lost: 1,288 bytes in 34 blocks
==13584==      possibly lost: 0 bytes in 0 blocks
==13584==    still reachable: 238 bytes in 6 blocks
==13584==         suppressed: 0 bytes in 0 blocks
==13584== Reachable blocks (those to which a pointer was found) are not shown.
==13584== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==13584==
==13584== For counts of detected and suppressed errors, rerun with: -v
==13584== ERROR SUMMARY: 44 errors from 6 contexts (suppressed: 0 from 0)

*/