A more sensible fix, move the MCA variable in the verbs common area.

opal/mca/common/verbs/common_verbs_basics.c

@@ -34,6 +34,8 @@
 const char *ibv_get_sysfs_path(void);
 #endif
 
+int opal_verbs_want_fork_support;
+
 #include "common_verbs.h"
 #include "opal/runtime/opal_params.h"
 #include "opal/util/show_help.h"
@@ -68,6 +70,16 @@ int opal_common_verbs_fork_test(void)
 {
     /* Make sure that ibv_fork_init is called before the calls to other memory registering verbs,
      * which will be called after this function */
+    opal_verbs_want_fork_support = 1;
+    ret = mca_base_var_register("opal", "opal", NULL, "verbs_want_fork_support",
+                    "Whether fork support is desired or not "
+                    "(negative = try to enable fork support, but continue even "
+                    "if it is not available, 0 = do not enable fork support, "
+                    "positive = try to enable fork support and fail if it is not available)",
+                    MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
+                    OPAL_INFO_LVL_8, MCA_BASE_VAR_SCOPE_ALL_EQ,
+                    &opal_verbs_want_fork_support);
+
 #ifdef HAVE_IBV_FORK_INIT
     if (0 != opal_verbs_want_fork_support) {
         /* Check if fork support is requested by the user */

opal/runtime/opal_params.c

@@ -275,16 +275,6 @@ int opal_register_params(void)
         return ret; 
     }
 
-    opal_verbs_want_fork_support = 1;
-    ret = mca_base_var_register("opal", "opal", NULL, "verbs_want_fork_support",
-                    "Whether fork support is desired or not "
-                    "(negative = try to enable fork support, but continue even "
-                    "if it is not available, 0 = do not enable fork support, "
-                    "positive = try to enable fork support and fail if it is not available)",
-                    MCA_BASE_VAR_TYPE_INT, NULL, 0, MCA_BASE_VAR_FLAG_SETTABLE,
-                    OPAL_INFO_LVL_8, MCA_BASE_VAR_SCOPE_ALL_EQ,
-                    &opal_verbs_want_fork_support);
-
     return OPAL_SUCCESS;
 }
 

opal/runtime/opal_params.h

@@ -30,8 +30,6 @@ extern char *opal_signal_string;
 extern char *opal_net_private_ipv4;
 extern char *opal_set_max_sys_limits;
 
-OPAL_DECLSPEC extern int opal_verbs_want_fork_support;
-
 #if OPAL_ENABLE_TIMING
 extern char *opal_timing_sync_file;
 extern char *opal_timing_output;