From f946604af87b8a39187d67bba70dfbd143966c1e Mon Sep 17 00:00:00 2001
From: tconley1428 <tconley1428@gmail.com>
Date: Tue, 28 Oct 2025 23:06:22 -0700
Subject: [PATCH] gh-140228: Avoid making unnecessary syscalls in linecache for
 frozen modules (GH-140377) (cherry picked from commit
 c41f84ff61c52e3ff7ef86b0c66208b29613d23d)

Co-authored-by: tconley1428 <tconley1428@gmail.com>
---
 Lib/linecache.py                                             | 5 ++++-
 .../Library/2025-10-28-17-43-51.gh-issue-140228.8kfHhO.rst   | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2025-10-28-17-43-51.gh-issue-140228.8kfHhO.rst

diff --git a/Lib/linecache.py b/Lib/linecache.py
index 87d7d6fda657e4..2b5a31b3e75bc1 100644
--- a/Lib/linecache.py
+++ b/Lib/linecache.py
@@ -131,9 +131,12 @@ def updatecache(filename, module_globals=None):
     if _source_unavailable(filename):
         return []
 
-    if filename.startswith('<frozen ') and module_globals is not None:
+    if filename.startswith('<frozen '):
         # This is a frozen module, so we need to use the filename
         # from the module globals.
+        if module_globals is None:
+            return []
+
         fullname = module_globals.get('__file__')
         if fullname is None:
             return []
diff --git a/Misc/NEWS.d/next/Library/2025-10-28-17-43-51.gh-issue-140228.8kfHhO.rst b/Misc/NEWS.d/next/Library/2025-10-28-17-43-51.gh-issue-140228.8kfHhO.rst
new file mode 100644
index 00000000000000..b3b692bae62c5d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-10-28-17-43-51.gh-issue-140228.8kfHhO.rst
@@ -0,0 +1 @@
+Avoid making unnecessary filesystem calls for frozen modules in :mod:`linecache` when the global module cache is not present.