# Copyright 2020 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Workaround for qemu-img bug on arm64 platforms with multiple cores.
Runs qemu-img command
with timeout
and retries the command
if it hangs.
See:
crbug.com/1046861 QEMU
is out of date; current version of qemu-img
is unstable
https://bugs.launchpad.net/qemu/+bug/1805256 qemu-img hangs on
rcu_call_ready_event logic
in Aarch64 when converting images
TODO(crbug.com/1046861): Remove this workaround when the bug
is fixed.
"""
import logging
import subprocess
import tempfile
import time
# qemu-img p99 run time on Cavium ThunderX2 servers is 26 seconds.
# Using 2x the p99 time as the timeout.
QEMU_IMG_TIMEOUT_SEC = 52
def _ExecQemuImgWithTimeout(command):
"""Execute qemu-img command in subprocess with timeout.
Returns:
None if command timed out
or return code
if command completed.
"""
logging.info(
'qemu-img starting')
command_output_file = tempfile.NamedTemporaryFile(
'w')
p = subprocess.Popen(command, stdout=command_output_file,
stderr=subprocess.STDOUT)
start_sec = time.time()
while p.poll()
is None and time.time() - start_sec < QEMU_IMG_TIMEOUT_SEC:
time.sleep(1)
stop_sec = time.time()
logging.info(
'qemu-img duration: %f' % float(stop_sec - start_sec))
if p.poll()
is None:
returncode =
None
p.kill()
p.wait()
else:
returncode = p.returncode
log_level = logging.WARN
if returncode
else logging.DEBUG
for line
in open(command_output_file.name,
'r'):
logging.log(log_level,
'qemu-img stdout: ' + line.strip())
return returncode
def ExecQemuImgWithRetry(command):
""" Execute qemu-img command in subprocess with 2 retries.
Raises CalledProcessError
if command does
not complete successfully.
"""
tries = 0
status =
None
while status
is None and tries <= 2:
tries += 1
status = _ExecQemuImgWithTimeout(command)
if status
is None:
raise subprocess.CalledProcessError(-1, command)
if status:
raise subprocess.CalledProcessError(status, command)
