diff --git a/scripts/tracetool/format/log_stap.py b/scripts/tracetool/format/log_stap.py
index 3e1186ae9c..0b6549d534 100644
--- a/scripts/tracetool/format/log_stap.py
+++ b/scripts/tracetool/format/log_stap.py
@@ -78,7 +78,12 @@ def c_fmt_to_stap(fmt):
     elif state == STATE_LITERAL:
         bits.append(literal)
 
-    fmt = re.sub("%(\d*)z(x|u|d)", "%\\1\\2", "".join(bits))
+    # All variables in systemtap are 64-bit in size
+    # The "%l" integer size qualifier is thus redundant
+    # and "%ll" is not valid at all. Similarly the size_t
+    # based "%z" size qualifier is not valid. We just
+    # strip all size qualifiers for sanity.
+    fmt = re.sub("%(\d*)(l+|z)(x|u|d)", "%\\1\\3", "".join(bits))
     return fmt
 
 def generate(events, backend, group):