--- a/hotspot/src/os/bsd/vm/attachListener_bsd.cpp	Tue Aug 16 09:56:18 2016 -0400
+++ b/hotspot/src/os/bsd/vm/attachListener_bsd.cpp	Thu Aug 18 14:07:00 2016 +0300
@@ -456,7 +456,7 @@
   if (ret == 0) {
     ret = ::unlink(fn);
     if (ret == -1) {
-      debug_only(warning("failed to remove stale attach pid file at %s", fn));
+      log_debug(attach)("Failed to remove stale attach pid file at %s", fn);
     }
   }
 }
@@ -493,19 +493,25 @@
   if (init_at_startup() || is_initialized()) {
     return false;               // initialized at startup or already initialized
   }
-  char path[PATH_MAX + 1];
+  char fn[PATH_MAX + 1];
   int ret;
   struct stat st;
 
-  snprintf(path, PATH_MAX + 1, "%s/.attach_pid%d",
+  snprintf(fn, PATH_MAX + 1, "%s/.attach_pid%d",
            os::get_temp_directory(), os::current_process_id());
-  RESTARTABLE(::stat(path, &st), ret);
+  RESTARTABLE(::stat(fn, &st), ret);
+  if (ret == -1) {
+    log_debug(attach)("Failed to find attach file: %s", fn);
+  }
   if (ret == 0) {
     // simple check to avoid starting the attach mechanism when
     // a bogus user creates the file
     if (st.st_uid == geteuid()) {
       init();
+      log_trace(attach)("Attach trigerred by %s", fn);
       return true;
+    } else {
+      log_debug(attach)("File %s has wrong user id %d (vs %d). Attach is not triggered", fn, st.st_uid, geteuid());
     }
   }
   return false;