From 8d892f9917567b32c773acc95eecd80ae7de8d9d Mon Sep 17 00:00:00 2001
From: George Bosilca <bosilca@icl.utk.edu>
Date: Fri, 9 Mar 2018 09:18:19 +0900
Subject: [PATCH] Be conservative with the array_of_indices We were assuming
 that the array_of_indices has the same size as the number of requests
 (incount), instead of the numberr of actually active requests. While the
 patch is trivial, the question of the size of the array_of_indices should be
 clarified in the MPI Forum.

Signed-off-by: George Bosilca <bosilca@icl.utk.edu>
(cherry picked from commit a5fbfa476a591e747bec285552b57a216c44c027)
---
 ompi/request/req_wait.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/ompi/request/req_wait.c b/ompi/request/req_wait.c
index e4d4d5e68a6..d8eb64984c4 100644
--- a/ompi/request/req_wait.c
+++ b/ompi/request/req_wait.c
@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2010 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2016 The University of Tennessee and The University
+ * Copyright (c) 2004-2018 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
@@ -388,13 +388,13 @@ int ompi_request_default_wait_some(size_t count,
                                    int * indices,
                                    ompi_status_public_t * statuses)
 {
-    size_t num_requests_null_inactive=0, num_requests_done=0;
+    size_t num_requests_null_inactive, num_requests_done, num_active_reqs;
     int rc = MPI_SUCCESS;
     ompi_request_t **rptr = NULL;
     ompi_request_t *request = NULL;
     ompi_wait_sync_t sync;
     size_t sync_sets = 0, sync_unsets = 0;
-    
+
     if (OPAL_UNLIKELY(0 == count)) {
         *outcount = MPI_UNDEFINED;
         return OMPI_SUCCESS;
@@ -407,6 +407,7 @@ int ompi_request_default_wait_some(size_t count,
     rptr = requests;
     num_requests_null_inactive = 0;
     num_requests_done = 0;
+    num_active_reqs = 0;
     for (size_t i = 0; i < count; i++, rptr++) {
         void *_tmp_ptr = REQUEST_PENDING;
 
@@ -419,14 +420,14 @@ int ompi_request_default_wait_some(size_t count,
             num_requests_null_inactive++;
             continue;
         }
-        indices[i] = OPAL_ATOMIC_COMPARE_EXCHANGE_STRONG_PTR(&request->req_complete, &_tmp_ptr, &sync);
-        if( !indices[i] ) {
+        indices[num_active_reqs] = OPAL_ATOMIC_COMPARE_EXCHANGE_STRONG_PTR(&request->req_complete, &_tmp_ptr, &sync);
+        if( !indices[num_active_reqs] ) {
             /* If the request is completed go ahead and mark it as such */
             assert( REQUEST_COMPLETE(request) );
             num_requests_done++;
         }
+        num_active_reqs++;
     }
-    sync_sets = count - num_requests_null_inactive - num_requests_done;
 
     if(num_requests_null_inactive == count) {
         *outcount = MPI_UNDEFINED;
@@ -435,6 +436,7 @@ int ompi_request_default_wait_some(size_t count,
         return rc;
     }
 
+    sync_sets = num_active_reqs - num_requests_done;
     if( 0 == num_requests_done ) {
         /* One completed request is enough to satisfy the some condition */
         SYNC_WAIT(&sync);
@@ -445,6 +447,7 @@ int ompi_request_default_wait_some(size_t count,
 
     rptr = requests;
     num_requests_done = 0;
+    num_active_reqs = 0;
     for (size_t i = 0; i < count; i++, rptr++) {
         void *_tmp_ptr = &sync;
 
@@ -466,13 +469,14 @@ int ompi_request_default_wait_some(size_t count,
          * either slowly (in case of partial completion)
          * OR in parallel with `i` (in case of full set completion)  
          */
-        if( !indices[i] ){
+        if( !indices[num_active_reqs] ) {
             indices[num_requests_done++] = i;
         } else if( !OPAL_ATOMIC_COMPARE_EXCHANGE_STRONG_PTR(&request->req_complete, &_tmp_ptr, REQUEST_PENDING) ) {
             indices[num_requests_done++] = i;
         }
+        num_active_reqs++;
     }
-    sync_unsets = count - num_requests_null_inactive - num_requests_done;
+    sync_unsets = num_active_reqs - num_requests_done;
 
     if( sync_sets == sync_unsets ){
         /* nobody knows about us,