Bug 242083

When the run-benchmark runner for Linux attempts to kill the browser first it kills the main browser process and then it kills all the browser subprocess if those are still alive. The issue is that there is a race condition between the check of the subprocess being alive and the kill call, sometimes the the child ends in the interval between the is_running() and kill() call causing an exception on the runner. This can be seen here https://build.webkit.org/#/builders/26/builds/2163/steps/13/logs/stdio 2022-06-28 08:58:10,070 - INFO - Cleaning Benchmark 2022-06-28 08:58:10,098 - ERROR - Error running benchmark plan: jetstream2 Traceback (most recent call last): File "/home/buildbot/worker/GTK-Linux-64-bit-Release-Perf/build/Tools/Scripts/webkitpy/browserperfdash/browserperfdash_runner.py", line 163, in run runner.execute() File "/home/buildbot/worker/GTK-Linux-64-bit-Release-Perf/build/Tools/Scripts/webkitpy/benchmark_runner/benchmark_runner.py", line 120, in execute self._run_benchmark(int(self._plan['count']), web_root) File "/home/buildbot/worker/GTK-Linux-64-bit-Release-Perf/build/Tools/Scripts/webkitpy/benchmark_runner/benchmark_runner.py", line 90, in _run_benchmark result = self._run_one_test(web_root, self._plan['entry_point']) File "/home/buildbot/worker/GTK-Linux-64-bit-Release-Perf/build/Tools/Scripts/webkitpy/benchmark_runner/webserver_benchmark_runner.py", line 61, in _run_one_test self._browser_driver.close_browsers() File "/home/buildbot/worker/GTK-Linux-64-bit-Release-Perf/build/Tools/Scripts/webkitpy/benchmark_runner/browser_driver/linux_browser_driver.py", line 85, in close_browsers browser_child.kill() File "/usr/lib/python3/dist-packages/psutil/__init__.py", line 383, in wrapper raise NoSuchProcess(self.pid, self._name) psutil.NoSuchProcess: psutil.NoSuchProcess process no longer exists (pid=9447)