diff --git a/src/debug_utils-inl.h b/src/debug_utils-inl.h
index 03b49490622d49..d5303bf41e50fe 100644
--- a/src/debug_utils-inl.h
+++ b/src/debug_utils-inl.h
@@ -32,14 +32,18 @@ std::string ToString(const T& value) {
 }
 
 inline std::string SPrintFImpl(const char* format) {
-  return format;
+  const char* p = strchr(format, '%');
+  if (LIKELY(p == nullptr)) return format;
+  CHECK(p[1] == '%');  // Only '%%' allowed when there are no arguments.
+
+  return std::string(format, p + 1) + SPrintFImpl(p + 2);
 }
 
 template <typename Arg, typename... Args>
 std::string COLD_NOINLINE SPrintFImpl(  // NOLINT(runtime/string)
     const char* format, Arg&& arg, Args&&... args) {
   const char* p = strchr(format, '%');
-  if (p == nullptr) return format;
+  CHECK_NOT_NULL(p);
   std::string ret(format, p);
   // Ignore long / size_t modifiers
   while (strchr("lz", *++p) != nullptr) {}
diff --git a/test/cctest/test_util.cc b/test/cctest/test_util.cc
index de9c5368bddfda..e3a4a700e96583 100644
--- a/test/cctest/test_util.cc
+++ b/test/cctest/test_util.cc
@@ -282,6 +282,8 @@ TEST(UtilTest, SPrintF) {
   EXPECT_EQ(SPrintF("%s %s", foo, "bar"), "foo bar");
   EXPECT_EQ(SPrintF("%s %s", foo, bar), "foo bar");
 
+  EXPECT_EQ(SPrintF("[%% %s %%]", foo), "[% foo %]");
+
   struct HasToString {
     std::string ToString() const {
       return "meow";