Merge pull request #6474 from abouteiller/backport/5975/v3.1.x

v3.1.x: Avoid a double lock interlock when calling pmix_finalize

Author: jsquyres

opal/mca/pmix/pmix2x/pmix2x_client.c

@@ -8,6 +8,9 @@
  * Copyright (c) 2016 Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2016      Los Alamos National Security, LLC. All rights
  *                         reserved.
+ * Copyright (c) 2018      The University of Tennessee and The University
+ *                         of Tennessee Research Foundation.  All rights
+ *                         reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -165,6 +168,8 @@ int pmix2x_client_finalize(void)
 {
     pmix_status_t rc;
     opal_pmix2x_event_t *event, *ev2;
+    opal_list_t evlist;
+    OBJ_CONSTRUCT(&evlist, opal_list_t);
 
     opal_output_verbose(1, opal_pmix_base_framework.framework_output,
                         "PMIx_client finalize");
@@ -178,12 +183,19 @@ int pmix2x_client_finalize(void)
             OPAL_PMIX_DESTRUCT_LOCK(&event->lock);
             OPAL_PMIX_CONSTRUCT_LOCK(&event->lock);
             PMIx_Deregister_event_handler(event->index, dereg_cbfunc, (void*)event);
-            OPAL_PMIX_WAIT_THREAD(&event->lock);
             opal_list_remove_item(&mca_pmix_pmix2x_component.events, &event->super);
-            OBJ_RELEASE(event);
+            /* wait and release outside the loop to avoid double mutex
+             * interlock */
+            opal_list_append(&evlist, &event->super);
         }
     }
     OPAL_PMIX_RELEASE_THREAD(&opal_pmix_base.lock);
+    OPAL_LIST_FOREACH_SAFE(event, ev2, &evlist, opal_pmix2x_event_t) {
+        OPAL_PMIX_WAIT_THREAD(&event->lock);
+        opal_list_remove_item(&evlist, &event->super);
+        OBJ_RELEASE(event);
+    }
+    OBJ_DESTRUCT(&evlist);
     rc = PMIx_Finalize(NULL, 0);
 
     return pmix2x_convert_rc(rc);

opal/mca/pmix/pmix2x/pmix2x_server_south.c

@@ -9,6 +9,9 @@
  * Copyright (c) 2016      Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2017      Los Alamos National Security, LLC. All rights
  *                         reserved.
+ * Copyright (c) 2018      The University of Tennessee and The University
+ *                         of Tennessee Research Foundation.  All rights
+ *                         reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -180,6 +183,8 @@ int pmix2x_server_finalize(void)
 {
     pmix_status_t rc;
     opal_pmix2x_event_t *event, *ev2;
+    opal_list_t evlist;
+    OBJ_CONSTRUCT(&evlist, opal_list_t);
 
     OPAL_PMIX_ACQUIRE_THREAD(&opal_pmix_base.lock);
     --opal_pmix_base.initialized;
@@ -190,13 +195,19 @@ int pmix2x_server_finalize(void)
             OPAL_PMIX_DESTRUCT_LOCK(&event->lock);
             OPAL_PMIX_CONSTRUCT_LOCK(&event->lock);
             PMIx_Deregister_event_handler(event->index, dereg_cbfunc, (void*)event);
-            OPAL_PMIX_WAIT_THREAD(&event->lock);
             opal_list_remove_item(&mca_pmix_pmix2x_component.events, &event->super);
-            OBJ_RELEASE(event);
+            /* wait and release outside the loop to avoid double mutex
+             * interlock */
+            opal_list_append(&evlist, &event->super);
         }
     }
     OPAL_PMIX_RELEASE_THREAD(&opal_pmix_base.lock);
-
+    OPAL_LIST_FOREACH_SAFE(event, ev2, &evlist, opal_pmix2x_event_t) {
+        OPAL_PMIX_WAIT_THREAD(&event->lock);
+        opal_list_remove_item(&evlist, &event->super);
+        OBJ_RELEASE(event);
+    }
+    OBJ_DESTRUCT(&evlist);
     rc = PMIx_server_finalize();
     return pmix2x_convert_rc(rc);
 }