Tweak tracepoint logic to run on tracepoint_synchronize_unregister()-less RHEL5

2 files changed, 18 insertions, 4 deletions

diff --git a/tapsets.cxx b/tapsets.cxx
index defaf385..5ea3982d 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -9764,9 +9764,15 @@ tracepoint_derived_probe_group::emit_module_init (systemtap_session &s)
                        << "(enter_tracepoint_probe_" << i << ");";
       s.op->newline(-2) << "}";
     }
-  s.op->newline() << "if (rc)";
-  s.op->newline(1) << "tracepoint_synchronize_unregister();";
-  s.op->indent(-1);
+
+  // This would be technically proper (on those autoconf-detectable
+  // kernels that include this function in tracepoint.h), however we
+  // already make several calls to synchronze_sched() during our
+  // shutdown processes.
+
+  // s.op->newline() << "if (rc)";
+  // s.op->newline(1) << "tracepoint_synchronize_unregister();";
+  // s.op->indent(-1);
 }
 
 
@@ -9780,7 +9786,10 @@ tracepoint_derived_probe_group::emit_module_exit (systemtap_session& s)
   for (unsigned i = 0; i < probes.size(); ++i)
     s.op->newline() << "unregister_trace_" << probes[i]->tracepoint_name
                     << "(enter_tracepoint_probe_" << i << ");";
-  s.op->newline() << "tracepoint_synchronize_unregister();";
+
+  // Not necessary: see above.
+
+  // s.op->newline() << "tracepoint_synchronize_unregister();";
 }
 
 
diff --git a/translate.cxx b/translate.cxx
index 23a24100..c679e0f1 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -1236,6 +1236,11 @@ c_unparser::emit_module_init ()
 	o->newline() << getvar (v).fini();
     }
 
+  // For any partially registered/unregistered kernel facilities.
+  o->newline() << "#ifdef STAPCONF_SYNCHRONIZE_SCHED";
+  o->newline() << "synchronize_sched();";
+  o->newline() << "#endif";
+
   o->newline() << "return rc;";
   o->newline(-1) << "}\n";
 }