From 9141f27cb56261f774dc08acbc251e5c851fda87 Mon Sep 17 00:00:00 2001
From: PalNilsson <Paul.Nilsson@cern.ch>
Date: Tue, 26 Nov 2024 10:15:59 +0100
Subject: [PATCH] Added verification that /proc/self/statm can be accessed

---
 pilot/util/monitoring.py | 17 +++++++++++------
 pilot/util/processes.py  | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/pilot/util/monitoring.py b/pilot/util/monitoring.py
index 2ca15413..42dde4d8 100644
--- a/pilot/util/monitoring.py
+++ b/pilot/util/monitoring.py
@@ -37,9 +37,9 @@
 from pilot.util.container import execute
 from pilot.util.filehandling import (
     get_disk_usage,
-    remove_files,
     get_local_file_size,
     read_file,
+    remove_files,
     zip_files,
     #write_file
 )
@@ -54,22 +54,23 @@
     get_maximum_input_sizes
 )
 from pilot.util.processes import (
+    check_proc_access,
     get_current_cpu_consumption_time,
-    kill_processes,
     get_number_of_child_processes,
+    kill_processes,
     reap_zombies
 )
 from pilot.util.psutils import (
     is_process_running,
     check_cpu_load,
+    find_actual_payload_pid,
     get_pid,
     get_subprocesses,
-    find_actual_payload_pid
 )
 from pilot.util.timing import get_time_since
 from pilot.util.workernode import (
+    check_hz,
     get_local_disk_space,
-    check_hz
 )
 from pilot.info import infosys, JobData
 
@@ -201,10 +202,14 @@ def set_cpu_consumption_time(job: JobData) -> tuple[int, str]:
                 else:
                     logger.debug(
                         f'CPU consumption time increased by a factor of {increase_factor} (below the limit of {factor})')
-                    job.cpuconsumptiontime = _cpuconsumptiontime
+
+                    # make sure that /proc/self/statm still exists, otherwise the job is no longer using CPU, ie discard the info
+                    if check_proc_access():
+                        logger.debug("/proc/self/statm exists - will update the CPU consumption time")
+                        job.cpuconsumptiontime = _cpuconsumptiontime
             job.cpuconversionfactor = 1.0
             logger.info(
-                f'(instant) CPU consumption time for pid={job.pid}: {cpuconsumptiontime} (rounded to {job.cpuconsumptiontime})')
+                f'(instant) CPU consumption time for pid={job.pid}: {job.cpuconsumptiontime})')
         elif _cpuconsumptiontime == -1:
             logger.warning('could not get CPU consumption time')
         elif _cpuconsumptiontime == 0:
diff --git a/pilot/util/processes.py b/pilot/util/processes.py
index 95d4eb8e..d6167e63 100644
--- a/pilot/util/processes.py
+++ b/pilot/util/processes.py
@@ -946,3 +946,18 @@ def waitpid(pid: int = -1):
             pass
     logger.info(f'reaping zombies for max {max_timeout} seconds')
     waitpid(pid)
+
+
+def check_proc_access() -> bool:
+    """
+    Verify that /proc/self/statm can be accessed.
+
+    :return: True if /proc/self/statm can be accessed, False otherwise (bool).
+    """
+    try:
+        with open('/proc/self/statm', 'r') as f:
+            _ = f.read()
+        return True
+    except (FileNotFoundError, PermissionError) as e:
+        logger.warning(f"error accessing /proc/self/statm: {e} (CPU consumption time will be discarded)")
+        return False