diff --git a/ompi/mca/osc/pt2pt/osc_pt2pt.h b/ompi/mca/osc/pt2pt/osc_pt2pt.h
index bbb35f55629..f011a052eed 100644
--- a/ompi/mca/osc/pt2pt/osc_pt2pt.h
+++ b/ompi/mca/osc/pt2pt/osc_pt2pt.h
@@ -912,11 +912,14 @@ static inline ompi_osc_pt2pt_sync_t *ompi_osc_pt2pt_module_sync_lookup (ompi_osc
 
         return &module->all_sync;
     case OMPI_OSC_PT2PT_SYNC_TYPE_PSCW:
+        OPAL_THREAD_LOCK(&module->all_sync.lock);
         if (ompi_osc_pt2pt_sync_pscw_peer (module, target, peer)) {
+            OPAL_THREAD_UNLOCK(&module->all_sync.lock);
             OPAL_OUTPUT_VERBOSE((50, ompi_osc_base_framework.framework_output,
                                  "osc/pt2pt: found PSCW access epoch target for %d", target));
             return &module->all_sync;
         }
+        OPAL_THREAD_UNLOCK(&module->all_sync.lock);
     }
 
     return NULL;
diff --git a/ompi/mca/osc/pt2pt/osc_pt2pt_active_target.c b/ompi/mca/osc/pt2pt/osc_pt2pt_active_target.c
index 55917ca65ae..b8b1d27b411 100644
--- a/ompi/mca/osc/pt2pt/osc_pt2pt_active_target.c
+++ b/ompi/mca/osc/pt2pt/osc_pt2pt_active_target.c
@@ -213,9 +213,11 @@ int ompi_osc_pt2pt_start (ompi_group_t *group, int assert, ompi_win_t *win)
     ompi_osc_pt2pt_sync_t *sync = &module->all_sync;
 
     OPAL_THREAD_LOCK(&module->lock);
+    OPAL_THREAD_LOCK(&sync->lock);
 
     /* check if we are already in an access epoch */
     if (ompi_osc_pt2pt_access_epoch_active (module)) {
+        OPAL_THREAD_UNLOCK(&sync->lock);
         OPAL_THREAD_UNLOCK(&module->lock);
         return OMPI_ERR_RMA_SYNC;
     }
@@ -249,6 +251,7 @@ int ompi_osc_pt2pt_start (ompi_group_t *group, int assert, ompi_win_t *win)
     if (0 == ompi_group_size (group)) {
         /* nothing more to do. this is an empty start epoch */
         sync->eager_send_active = true;
+        OPAL_THREAD_UNLOCK(&sync->lock);
         OPAL_THREAD_UNLOCK(&module->lock);
         return OMPI_SUCCESS;
     }
@@ -258,12 +261,12 @@ int ompi_osc_pt2pt_start (ompi_group_t *group, int assert, ompi_win_t *win)
     /* translate the group ranks into the communicator */
     sync->peer_list.peers = ompi_osc_pt2pt_get_peers (module, group);
     if (NULL == sync->peer_list.peers) {
+        OPAL_THREAD_UNLOCK(&sync->lock);
         OPAL_THREAD_UNLOCK(&module->lock);
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
 
     if (!(assert & MPI_MODE_NOCHECK)) {
-        OPAL_THREAD_LOCK(&sync->lock);
         for (int i = 0 ; i < sync->num_peers ; ++i) {
             ompi_osc_pt2pt_peer_t *peer = sync->peer_list.peers[i];
 
@@ -276,7 +279,6 @@ int ompi_osc_pt2pt_start (ompi_group_t *group, int assert, ompi_win_t *win)
                 ompi_osc_pt2pt_peer_set_unex (peer, false);
             }
         }
-        OPAL_THREAD_UNLOCK(&sync->lock);
     } else {
         sync->sync_expected = 0;
     }
@@ -295,6 +297,7 @@ int ompi_osc_pt2pt_start (ompi_group_t *group, int assert, ompi_win_t *win)
                          "ompi_osc_pt2pt_start complete. eager sends active: %d",
                          sync->eager_send_active));
 
+    OPAL_THREAD_UNLOCK(&sync->lock);
     OPAL_THREAD_UNLOCK(&module->lock);
     return OMPI_SUCCESS;
 }
diff --git a/ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c b/ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c
index 04333d2add4..bacfab86b9a 100644
--- a/ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c
+++ b/ompi/mca/osc/pt2pt/osc_pt2pt_data_move.c
@@ -747,7 +747,9 @@ static int ompi_osc_pt2pt_acc_op_queue (ompi_osc_pt2pt_module_t *module, ompi_os
     }
 
     /* add to the pending acc queue */
-    OPAL_THREAD_SCOPED_LOCK(&module->lock, opal_list_append (&module->pending_acc, &pending_acc->super));
+    ompi_osc_pt2pt_accumulate_lock(module);
+    opal_list_append (&module->pending_acc, &pending_acc->super);
+    ompi_osc_pt2pt_accumulate_unlock(module);
 
     return OMPI_SUCCESS;
 }