[mvapich-discuss] FW: Possible bug: Segmentation fault with
MPI_Reduce and MPI_IN_PLACE
Alexander Alekhin
alexander.alekhin at itseez.com
Mon Nov 22 11:06:20 EST 2010
Hi,
I use MVAPICH2 1.5.1p1 code from svn.
My mpiname info:
MVAPICH2 1.5.1p1 Unofficial Build ch3:mrail
Compilation
CC: gcc -g
CXX: c++ -g
F77: g77 -g
F90: f95 -g
Configuration
--prefix=$HOME/mvapich2/install --enable-g=all --enable-error-messages=all --enable-fast=none
My problem is in application failure which uses MPI_IN_PLACE with MPI_Reduce operation.
For example I provide this part of code which generate a segmentation fault with 2 processes launched on same node:
// myid is rank in MPI_COMM_WORLD (see examples/cpi.c)
{
MPI_Group g1, g2;
MPI_Comm comm;
int ranks[2] = { 1, 0 };
MPI_Comm_group(MPI_COMM_WORLD, &g1);
MPI_Group_incl(g1, 2, ranks, &g2);
MPI_Comm_create(MPI_COMM_WORLD, g2, &comm);
if (myid == 0) { // rank 1 of comm (root of Reduce)
int result = myid;
if (MPI_Reduce(MPI_IN_PLACE, &result, 1, MPI_INT, MPI_SUM, 1, comm) != MPI_SUCCESS) // fail is here
exit(1);
} else {
if (MPI_Reduce(&myid, NULL, 1, MPI_INT, MPI_SUM, 1, comm) != MPI_SUCCESS)
exit(1);
}
MPI_Comm_free(&comm);
MPI_Group_free(&g2);
MPI_Group_free(&g1);
}
Command to launch:
mpiexec -np 2 -host <host_name> <binary_file>
GDB info:
0: Program received signal SIGSEGV, Segmentation fault.
0: 0x0000000000411a73 in MPIUI_Memcpy (dst=0x2aaaaadcfc0c,
0: src=0xffffffffffffffff, len=4) at ../../include/mpiimpl.h:122
0: 122 memcpy(dst, src, len);
0: (gdb) bt
0: #0 0x0000000000411a73 in MPIUI_Memcpy (dst=0x2aaaaadcfc0c,
0: src=0xffffffffffffffff, len=4) at ../../include/mpiimpl.h:122
0: #1 0x0000000000414eb3 in MPIR_Localcopy (sendbuf=0xffffffffffffffff,
0: sendcount=1, sendtype=1275069445, recvbuf=0x2aaaaadcfc0c, recvcount=1,
0: recvtype=1275069445) at helper_fns.c:335
0: #2 0x0000000000410d48 in PMPI_Reduce (sendbuf=0xffffffffffffffff,
0: recvbuf=0x7fffcb044bcc, count=1, datatype=1275069445, op=1476395011,
0: root=1, comm=-1006632960) at reduce_osu.c:1017
If I replace MPI_IN_PLACE to variable then all works fine.
Can somebody check this problem?
--
Thanks,
Alexander Alekhin
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