diff --git a/master.cfg b/master.cfg
index 0685fcf..984ad91 100644
--- a/master.cfg
+++ b/master.cfg
@@ -142,8 +142,8 @@ import smtplib
 import socket
 from email.mime.text import MIMEText
 
-def make_try_build_lockfile_name (rev):
-    return "/tmp/gdb-buildbot-%s-try.lock" % rev
+def make_try_build_lockfile_name (msgid):
+    return "/tmp/gdb-buildbot-%s-try.lock" % msgid
 
 def SendRootMessageGDBTesters (branch, change, rev,
                                istrysched = False,
@@ -153,7 +153,7 @@ def SendRootMessageGDBTesters (branch, change, rev,
     global GDB_MAIL_TO, GDB_MAIL_FROM
 
     if istrysched:
-        f = make_try_build_lockfile_name (rev)
+        f = make_try_build_lockfile_name (try_msgid)
     else:
         f = "/tmp/gdb-buildbot-%s.lock" % rev