Resolve race condition in Process.threads() (#2151)

* Resolve race condition in Process.threads() Process.threads() has a race condition triggered when a thread exits after the open_binary() call and before the read() call. When this happens, the read() call raises ProcessLookupError. Handle the race condition by catching ProcessLookupError from read() and treating the same as a FileNotFoundError from open_binary(). This is the same approach used in ppid_map(). Signed-off-by: Daniel Li <[email protected]> * Also catch ProcessLookupError in open_files() Signed-off-by: Daniel Li <[email protected]>
giampaolo · Sep 29, 2022 · 052c1e2 · 052c1e2
1 parent 69b572e
commit 052c1e2
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diff --git a/CREDITS b/CREDITS
@@ -798,3 +798,6 @@ N: Bernhard Urban-Forster
 C: Austria
 W: https://github.com/lewurm
 I: 2135
+
+N: Daniel Li
+I: 2150
diff --git a/HISTORY.rst b/HISTORY.rst
@@ -14,6 +14,8 @@ XXXX-XX-XX
   undefined ``ethtool_cmd_speed`` symbol.
 - 2142_, [POSIX]: `net_if_stats()`_ 's ``flags`` on Python 2 returned unicode
   instead of str.  (patch by Matthieu Darbois)
+- 2150_, [Linux] `Process.threads()`_ may raise ``NoSuchProcess``. Fix race
+  condition.  (patch by Daniel Li)
 
 5.9.2
 =====

diff --git a/psutil/_pslinux.py b/psutil/_pslinux.py
@@ -2061,9 +2061,9 @@ def threads(self):
             try:
                 with open_binary(fname) as f:
                     st = f.read().strip()
-            except FileNotFoundError:
-                # no such file or directory; it means thread
-                # disappeared on us
+            except (FileNotFoundError, ProcessLookupError):
+                # no such file or directory or no such process;
+                # it means thread disappeared on us
                 hit_enoent = True
                 continue
             # ignore the first two values ("pid (exe)")
@@ -2217,7 +2217,7 @@ def open_files(self):
                         with open_binary(file) as f:
                             pos = int(f.readline().split()[1])
                             flags = int(f.readline().split()[1], 8)
-                    except FileNotFoundError:
+                    except (FileNotFoundError, ProcessLookupError):
                         # fd gone in the meantime; process may
                         # still be alive
                         hit_enoent = True