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Lunev" Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, Hanna Reitz Subject: Re: [PATCH 1/3] iotests: run the test pool with the 'fork' start method Message-ID: References: <20260710161309.1104712-1-den@openvz.org> <20260710161309.1104712-2-den@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260710161309.1104712-2-den@openvz.org> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: permerror client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.01, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 10.07.2026 um 18:13 hat Denis V. Lunev geschrieben: > run_tests_pool() shares the runner via the class attribute > TestRunner.shared_self, relying on worker processes to inherit it. > That only works with the 'fork' start method. Python 3.14 switched > the Linux default to 'forkserver', so workers see shared_self as > None and parallel runs abort with: > > assert runner is not None > AssertionError > > Only reproduces with Python 3.14+ and 'check -jN' (N > 1); meson > runs one test per process and never calls run_tests_pool(), so CI > is unaffected. > > Request get_context('fork') explicitly; it is available on all > supported Python versions and a no-op before 3.14. > > Signed-off-by: Denis V. Lunev > CC: Kevin Wolf > CC: Hanna Reitz > --- > tests/qemu-iotests/testrunner.py | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/tests/qemu-iotests/testrunner.py b/tests/qemu-iotests/testrunner.py > index dbe2dddc32..5b2664d9f3 100644 > --- a/tests/qemu-iotests/testrunner.py > +++ b/tests/qemu-iotests/testrunner.py > @@ -26,7 +26,7 @@ > import json > import shutil > import sys > -from multiprocessing import Pool > +from multiprocessing import Pool, get_context > from typing import List, Optional, Any, Sequence, Dict > from testenv import TestEnv > > @@ -125,7 +125,7 @@ def run_tests_pool(self, tests: List[str], > assert TestRunner.shared_self is None > TestRunner.shared_self = self > > - with Pool(jobs) as p: > + with get_context('fork').Pool(jobs) as p: > results = p.starmap(self.proc_run_test, > zip(tests, [test_field_width] * len(tests))) Makes sense, but the Pool import is now unused: === pylint === +************* Module testrunner +testrunner.py:29:0: W0611: Unused Pool imported from multiprocessing (unused-import) === mypy === Kevin