diff --git a/MC/bin/o2_dpg_workflow_runner.py b/MC/bin/o2_dpg_workflow_runner.py
index ce47f184a..bcd6e098c 100755
--- a/MC/bin/o2_dpg_workflow_runner.py
+++ b/MC/bin/o2_dpg_workflow_runner.py
@@ -40,6 +40,40 @@ def setup_logger(name, log_file, level=logging.INFO):
 metriclogger = setup_logger('pipeline_metric_logger', 'pipeline_metric.log')
 
 
+# A fallback solution to getting all child procs
+# in case psutil has problems (PermissionError).
+# It returns the same list as psutil.children(recursive=True).
+def getChildProcs(basepid):
+  cmd='''
+  childprocs() {
+  local parent=$1
+  if [ ! "$2" ]; then
+    child_pid_list=""
+  fi
+  if [ "$parent" ] ; then
+    child_pid_list="$child_pid_list $parent"
+    for childpid in $(pgrep -P ${parent}); do
+      childprocs $childpid "nottoplevel"
+    done;
+  fi
+  # return via a string list (only if toplevel)
+  if [ ! "$2" ]; then
+    echo "${child_pid_list}"
+  fi
+  }
+  '''
+  cmd = cmd + '\n' + 'childprocs ' + str(basepid)
+  output = subprocess.check_output(cmd, shell=True)
+  plist = []
+  for p in output.strip().split():
+     try:
+         proc=psutil.Process(int(p))
+     except psutil.NoSuchProcess:
+         continue
+         
+     plist.append(proc)
+  return plist
+  
 #
 # Code section to find all topological orderings
 # of a DAG. This is used to know when we can schedule
@@ -363,20 +397,28 @@ def __init__(self, workflowfile, args, jmax=100):
     def SIGHandler(self, signum, frame):
        # basically forcing shut down of all child processes
        actionlogger.info("Signal " + str(signum) + " caught")
-       procs = psutil.Process().children(recursive=True)
+       try:
+           procs = psutil.Process().children(recursive=True)
+       except (psutil.NoSuchProcess):
+           pass
+       except (psutil.AccessDenied, PermissionError):
+           procs = getChildProcs(os.getpid())
+
        for p in procs:
            actionlogger.info("Terminating " + str(p))
            try:
-               p.terminate()
+             p.terminate()
            except (psutil.NoSuchProcess, psutil.AccessDenied):
-               pass
+             pass
+   
        gone, alive = psutil.wait_procs(procs, timeout=3)
        for p in alive:
-           actionlogger.info("Killing " + str(p))
            try:
-               p.kill()
+             actionlogger.info("Killing " + str(p))
+             p.kill()
            except (psutil.NoSuchProcess, psutil.AccessDenied):
-               pass
+             pass
+
        exit (1)
 
     def getallrequirements(self, t):
@@ -434,6 +476,7 @@ def submit(self, tid, nice=0):
           p.nice(nice)
           self.nicevalues[tid]=nice
       except (psutil.NoSuchProcess, psutil.AccessDenied):
+          actionlogger.error('Couldn\'t set nice value of ' + str(p.pid) + ' to ' + str(nice) + ' -- current value is ' + str(p.nice()))
           self.nicevalues[tid]=0
       return p
 
@@ -539,9 +582,12 @@ def monitor(self, process_list):
                 psutilProcs = [ proc ]
                 # use psutil for CPU measurement
                 psutilProcs = psutilProcs + proc.children(recursive=True)
-            except (psutil.NoSuchProcess, psutil.AccessDenied):
+            except (psutil.NoSuchProcess):
                 continue
 
+            except (psutil.AccessDenied, PermissionError):
+                psutilProcs = psutilProcs + getChildProcs(pid)
+
             # accumulate total metrics (CPU, memory)
             totalCPU = 0.
             totalPSS = 0.