group: Fix ompi_group_have_remote_peers

`ompi_group_t::grp_proc_pointers[i]` may have sentinel values even
for processes which reside in the local node because the array for
`MPI_COMM_WORLD` is set up before `ompi_proc_complete_init`, which
allocates `ompi_proc_t` objects for processes reside in the local
node, is called in `MPI_INIT`. So using `ompi_proc_is_sentinel`
against `ompi_group_t::grp_proc_pointers[i]` in order to determine
whether the process resides in a remote node is not appropriate.

This bug sometimes causes an `MPI_ERR_RMA_SHARED` error when
`MPI_WIN_ALLOCATE_SHARED` is called, where sm OSC uses
`ompi_group_have_remote_peers`.

Signed-off-by: KAWASHIMA Takahiro <[email protected]>

Author: kawashima-fj

ompi/group/group.c

@@ -563,10 +563,13 @@ bool ompi_group_have_remote_peers (ompi_group_t *group)
 #if OMPI_GROUP_SPARSE
         proc = ompi_group_peer_lookup (group, i);
 #else
-        if (ompi_proc_is_sentinel (group->grp_proc_pointers[i])) {
+        proc = ompi_group_get_proc_ptr_raw (group, i);
+        if (NULL == proc) {
+            /* the proc must be stored in the group or cached in the proc
+             * hash table if the process resides in the local node
+             * (see ompi_proc_complete_init) */
             return true;
         }
-        proc = group->grp_proc_pointers[i];
 #endif
         if (!OPAL_PROC_ON_LOCAL_NODE(proc->super.proc_flags)) {
             return true;