[test] Clean up stray processes before running tests on swarming

Bug: v8:10680
Change-Id: I3a6055372b757fac4c5e28840536d1389e857437
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2297381Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68868}

tools/testrunner/base_runner.py

@@ -33,6 +33,7 @@ from testrunner.testproc.rerun import RerunProc
 from testrunner.testproc.shard import ShardProc
 from testrunner.testproc.sigproc import SignalProc
 from testrunner.testproc.timeout import TimeoutProc
+from testrunner.testproc import util
 
 
 BASE_DIR = (
@@ -266,6 +267,9 @@ class BaseTestRunner(object):
         # this less cryptic by printing it ourselves.
         print(' '.join(sys.argv))
 
+        # Kill stray processes from previous tasks on swarming.
+        util.kill_processes_linux()
+
       self._load_build_config(options)
       command.setup(self.target_os, options.device)
 

tools/testrunner/testproc/progress.py

@@ -10,17 +10,11 @@ import datetime
 import json
 import os
 import platform
-import subprocess
 import sys
 import time
-from . import util
 
 from . import base
-
-
-# Base dir of the build products for Release and Debug.
-OUT_DIR = os.path.abspath(
-    os.path.join(os.path.dirname(__file__), '..', '..', '..', 'out'))
+from . import util
 
 
 def print_failure_header(test):
@@ -165,16 +159,10 @@ class VerboseProgressIndicator(SimpleProgressIndicator):
   # feedback channel from the workers, providing which tests are currently run.
   def _print_processes_linux(self):
     if platform.system() == 'Linux':
-      try:
-        cmd = 'ps -aux | grep "%s"' % OUT_DIR
-        output = subprocess.check_output(cmd, shell=True)
-        self._print('List of processes:')
-        for line in (output or '').splitlines():
-          # Show command with pid, but other process info cut off.
-          self._print('pid: %s cmd: %s' %
-                      (line.split()[1], line[line.index(OUT_DIR):]))
-      except:
-        pass
+      self._print('List of processes:')
+      for pid, cmd in util.list_processes_linux():
+        # Show command with pid, but other process info cut off.
+        self._print('pid: %d cmd: %s' % (pid, cmd))
 
   def _ensure_delay(self, delay):
     return time.time() - self._last_printed_time > delay

tools/testrunner/testproc/util.py

@@ -4,7 +4,49 @@
 # found in the LICENSE file.
 
 import heapq
+import os
+import platform
 import random
+import signal
+import subprocess
+
+# Base dir of the build products for Release and Debug.
+OUT_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..', '..', '..', 'out'))
+
+
+def list_processes_linux():
+  """Returns list of tuples (pid, command) of processes running in the same out
+  directory as this checkout.
+  """
+  if platform.system() != 'Linux':
+    return []
+  try:
+    cmd = 'pgrep -fa %s' % OUT_DIR
+    output = subprocess.check_output(cmd, shell=True) or ''
+    processes = [
+      (int(line.split()[0]), line[line.index(OUT_DIR):])
+      for line in output.splitlines()
+    ]
+    # Filter strange process with name as out dir.
+    return [p for p in processes if p[1] != OUT_DIR]
+  except:
+    return []
+
+
+def kill_processes_linux():
+  """Kill stray processes on the system that started in the same out directory.
+
+  All swarming tasks share the same out directory location.
+  """
+  if platform.system() != 'Linux':
+    return
+  for pid, cmd in list_processes_linux():
+    try:
+      print('Attempting to kill %d - %s' % (pid, cmd))
+      os.kill(pid, signal.SIGKILL)
+    except:
+      pass
 
 
 class FixedSizeTopList():