test.test_asyncio.test_server.TestServer2.test_abort_clients consistently fails on Linux 6.10.x

[hroncok]

Bug report

Bug description:

Hello, we run the testsuite of the optimized and debug builds of Python in Fedora CI. Since the addition in 4159644 the test has constantly failed like this on Fedora Rawhide / Fedora Linux 41 (the development version). It passes on Fedora 40 and 39.

======================================================================
FAIL: test_abort_clients (test.test_asyncio.test_server.TestServer2.test_abort_clients)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "/usr/lib64/python3.13/unittest/async_case.py", line 93, in _callTestMethod
 if self._callMaybeAsync(method) is not None:
 ~~~~~~~~~~~~~~~~~~~~^^^^^^^^
 File "/usr/lib64/python3.13/unittest/async_case.py", line 115, in _callMaybeAsync
 return self._asyncioRunner.run(
 ~~~~~~~~~~~~~~~~~~~~~~~^
 func(*args, **kwargs),
 ^^^^^^^^^^^^^^^^^^^^^^
 context=self._asyncioTestContext,
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 )
 ^
 File "/usr/lib64/python3.13/asyncio/runners.py", line 118, in run
 return self._loop.run_until_complete(task)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
 File "/usr/lib64/python3.13/asyncio/base_events.py", line 721, in run_until_complete
 return future.result()
 ~~~~~~~~~~~~~^^
 File "/usr/lib64/python3.13/test/test_asyncio/test_server.py", line 249, in test_abort_clients
 self.assertNotEqual(s_wr.transport.get_write_buffer_size(), 0)
 ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 0 == 0

----------------------------------------------------------------------

I was unable to reproduce this outside of Fedora CI. Perhaps this has to do with how the network is configured, no idea.

This is the output of python3.13 -m test.pythoninfo:

Details

Python debug information
========================

CC.version: gcc (GCC) 14.1.1 20240701 (Red Hat 14.1.1-7)
_decimal.__libmpdec_version__: 2.5.1
_testcapi.LONG_MAX: 9223372036854775807
_testcapi.PY_SSIZE_T_MAX: 9223372036854775807
_testcapi.Py_C_RECURSION_LIMIT: 10000
_testcapi.SIZEOF_TIME_T: 8
_testcapi.SIZEOF_WCHAR_T: 4
_testinternalcapi.SIZEOF_PYGC_HEAD: 16
_testinternalcapi.SIZEOF_PYOBJECT: 16
build.NDEBUG: ignore assertions (macro defined)
build.Py_DEBUG: No (sys.gettotalrefcount() missing)
build.Py_TRACE_REFS: No (sys.getobjects() missing)
build.WITH_DOC_STRINGS: Yes
build.WITH_DTRACE: Yes
build.WITH_FREELISTS: Yes
build.WITH_MIMALLOC: Yes
build.WITH_PYMALLOC: Yes
build.WITH_VALGRIND: Yes
builtins.float.double_format: IEEE, little-endian
builtins.float.float_format: IEEE, little-endian
config[_config_init]: 2
config[_init_main]: True
config[_install_importlib]: True
config[_is_python_build]: False
config[argv]: ['-m']
config[base_exec_prefix]: '/usr'
config[base_executable]: '/usr/bin/python3.13'
config[base_prefix]: '/usr'
config[buffered_stdio]: True
config[bytes_warning]: 0
config[check_hash_pycs_mode]: 'default'
config[code_debug_ranges]: True
config[configure_c_stdio]: True
config[cpu_count]: -1
config[dev_mode]: False
config[dump_refs]: False
config[dump_refs_file]: None
config[exec_prefix]: '/usr'
config[executable]: '/usr/bin/python3.13'
config[faulthandler]: False
config[filesystem_encoding]: 'utf-8'
config[filesystem_errors]: 'surrogateescape'
config[hash_seed]: 0
config[home]: None
config[import_time]: False
config[inspect]: False
config[install_signal_handlers]: True
config[int_max_str_digits]: 4300
config[interactive]: False
config[isolated]: False
config[malloc_stats]: False
config[module_search_paths]: ['/usr/lib64/python313.zip', '/usr/lib64/python3.13', '/usr/lib64/python3.13/lib-dynload']
config[module_search_paths_set]: True
config[optimization_level]: 0
config[orig_argv]: ['python3.13', '-m', 'test.pythoninfo']
config[parse_argv]: True
config[parser_debug]: False
config[pathconfig_warnings]: True
config[perf_profiling]: 0
config[platlibdir]: 'lib64'
config[prefix]: '/usr'
config[program_name]: 'python3.13'
config[pycache_prefix]: None
config[pythonpath_env]: None
config[quiet]: False
config[run_command]: None
config[run_filename]: None
config[run_module]: 'test.pythoninfo'
config[safe_path]: False
config[show_ref_count]: False
config[site_import]: True
config[skip_source_first_line]: False
config[stdio_encoding]: 'utf-8'
config[stdio_errors]: 'strict'
config[stdlib_dir]: '/usr/lib64/python3.13'
config[sys_path_0]: '/var/str/python/selftest'
config[tracemalloc]: 0
config[use_environment]: True
config[use_frozen_modules]: True
config[use_hash_seed]: False
config[user_site_directory]: True
config[verbose]: 0
config[warn_default_encoding]: False
config[warnoptions]: []
config[write_bytecode]: True
config[xoptions]: []
curses.ncurses_version: curses.ncurses_version(major=6, minor=4, patch=20240127)
datetime.datetime.now: 2024-07-22 16:05:29.258162
expat.EXPAT_VERSION: expat_2.6.2
fips.linux_crypto_fips_enabled: 0
fips.openssl_fips_mode: 0
gdb_version: GNU gdb (Fedora Linux) 14.2-14.fc41
gdbm.GDBM_VERSION: 1.23.0
global_config[Py_BytesWarningFlag]: 0
global_config[Py_DebugFlag]: 0
global_config[Py_DontWriteBytecodeFlag]: 0
global_config[Py_FileSystemDefaultEncodeErrors]: 'surrogateescape'
global_config[Py_FileSystemDefaultEncoding]: 'utf-8'
global_config[Py_FrozenFlag]: 0
global_config[Py_HasFileSystemDefaultEncoding]: 0
global_config[Py_HashRandomizationFlag]: 1
global_config[Py_IgnoreEnvironmentFlag]: 0
global_config[Py_InspectFlag]: 0
global_config[Py_InteractiveFlag]: 0
global_config[Py_IsolatedFlag]: 0
global_config[Py_NoSiteFlag]: 0
global_config[Py_NoUserSiteDirectory]: 0
global_config[Py_OptimizeFlag]: 0
global_config[Py_QuietFlag]: 0
global_config[Py_UTF8Mode]: 0
global_config[Py_UnbufferedStdioFlag]: 0
global_config[Py_VerboseFlag]: 0
global_config[_Py_HasFileSystemDefaultEncodeErrors]: 0
libregrtests.build_info: release shared LTO+PGO valgrind dtrace
locale.getencoding: UTF-8
os.cpu_count: 2
os.environ[HOME]: /root
os.environ[LANG]: en_US.UTF-8
os.environ[PATH]: /root/.local/bin:/root/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/var/str/python/selftest
os.environ[SHELL]: /bin/bash
os.environ[TERM]: xterm
os.getcwd: /var/str/python/selftest
os.getegid: 0
os.geteuid: 0
os.getgid: 0
os.getgrouplist: 0
os.getgroups: 0
os.getloadavg: (1.19873046875, 0.60791015625, 0.2412109375)
os.getrandom: ready (initialized)
os.getresgid: (0, 0, 0)
os.getresuid: (0, 0, 0)
os.getuid: 0
os.login: root
os.name: posix
os.process_cpu_count: 2
os.supports_bytes_environ: True
os.supports_effective_ids: ['access']
os.supports_fd: ['chdir', 'chmod', 'chown', 'execve', 'listdir', 'pathconf', 'scandir', 'stat', 'statvfs', 'truncate', 'utime']
os.supports_follow_symlinks: ['access', 'chown', 'link', 'stat', 'utime']
os.umask: 0o022
os.uname: posix.uname_result(sysname='Linux', nodename='ip-172-31-17-184.us-east-2.compute.internal', release='6.11.0-0.rc0.20240719git720261cfc732.7.fc41.x86_64', version='#1 SMP PREEMPT_DYNAMIC Fri Jul 19 16:59:06 UTC 2024', machine='x86_64')
platform.architecture: 64bit ELF
platform.freedesktop_os_release[ID]: fedora
platform.freedesktop_os_release[NAME]: Fedora Linux
platform.freedesktop_os_release[VARIANT_ID]: cloud
platform.freedesktop_os_release[VERSION]: 41 (Cloud Edition Prerelease)
platform.freedesktop_os_release[VERSION_ID]: 41
platform.libc_ver: glibc 2.39.9000
platform.platform: Linux-6.11.0-0.rc0.20240719git720261cfc732.7.fc41.x86_64-x86_64-with-glibc2.39.9000
platform.python_implementation: CPython
pre_config[_config_init]: 2
pre_config[allocator]: 0
pre_config[coerce_c_locale]: 0
pre_config[coerce_c_locale_warn]: 0
pre_config[configure_locale]: 1
pre_config[dev_mode]: 0
pre_config[isolated]: 0
pre_config[parse_argv]: 1
pre_config[use_environment]: 1
pre_config[utf8_mode]: 0
pwd.getpwuid(0): pwd.struct_passwd(pw_name='root', pw_passwd='x', pw_uid=0, pw_gid=0, pw_gecos='Super User', pw_dir='/root', pw_shell='/bin/bash')
pymem.allocator: pymalloc
readline._READLINE_LIBRARY_VERSION: 8.2
readline._READLINE_RUNTIME_VERSION: 0x802
readline._READLINE_VERSION: 0x802
resource.RLIMIT_AS: (-1, -1)
resource.RLIMIT_CORE: (-1, -1)
resource.RLIMIT_CPU: (-1, -1)
resource.RLIMIT_DATA: (-1, -1)
resource.RLIMIT_FSIZE: (-1, -1)
resource.RLIMIT_MEMLOCK: (8388608, 8388608)
resource.RLIMIT_MSGQUEUE: (819200, 819200)
resource.RLIMIT_NICE: (0, 0)
resource.RLIMIT_NOFILE: (1024, 524288)
resource.RLIMIT_NPROC: (15042, 15042)
resource.RLIMIT_OFILE: (1024, 524288)
resource.RLIMIT_RSS: (-1, -1)
resource.RLIMIT_RTPRIO: (0, 0)
resource.RLIMIT_RTTIME: (-1, -1)
resource.RLIMIT_SIGPENDING: (15042, 15042)
resource.RLIMIT_STACK: (8388608, -1)
resource.pagesize: 4096
socket.hostname: ip-172-31-17-184.us-east-2.compute.internal
sqlite3.sqlite_version: 3.46.0
ssl.HAS_SNI: True
ssl.OPENSSL_VERSION: OpenSSL 3.2.2 4 Jun 2024
ssl.OPENSSL_VERSION_INFO: (3, 2, 0, 2, 0)
ssl.OP_ALL: 0x80000050
ssl.OP_NO_TLSv1_1: 0x10000000
ssl.SSLContext.maximum_version: -1
ssl.SSLContext.minimum_version: -2
ssl.SSLContext.options: 2186412112
ssl.SSLContext.protocol: 16
ssl.SSLContext.verify_mode: 2
ssl.default_https_context.maximum_version: -1
ssl.default_https_context.minimum_version: -2
ssl.default_https_context.options: 2186412112
ssl.default_https_context.protocol: 16
ssl.default_https_context.verify_mode: 2
ssl.environ[OPENSSL_CONF]: /non-existing-file
ssl.stdlib_context.maximum_version: -1
ssl.stdlib_context.minimum_version: -2
ssl.stdlib_context.options: 2186412112
ssl.stdlib_context.protocol: 16
ssl.stdlib_context.verify_mode: 0
subprocess._USE_POSIX_SPAWN: True
support.MS_WINDOWS: False
support._is_gui_available: False
support.check_sanitizer(address=True): False
support.check_sanitizer(memory=True): False
support.check_sanitizer(ub=True): False
support.has_fork_support: True
support.has_socket_support: True
support.has_strftime_extensions: True
support.has_subprocess_support: True
support.is_android: False
support.is_emscripten: False
support.is_jython: False
support.is_wasi: False
support.python_is_optimized: True
support_os_helper.can_chmod: True
support_os_helper.can_dac_override: True
support_os_helper.can_symlink: True
support_os_helper.can_xattr: True
support_socket_helper.IPV6_ENABLED: True
support_socket_helper.has_gethostname: True
support_socket_helper.tcp_blackhole: False
support_threading_helper.can_start_thread: True
sys._is_gil_enabled: True
sys.api_version: 1013
sys.builtin_module_names: ('_abc', '_ast', '_codecs', '_collections', '_functools', '_imp', '_io', '_locale', '_operator', '_signal', '_sre', '_stat', '_string', '_suggestions', '_symtable', '_sysconfig', '_thread', '_tokenize', '_tracemalloc', '_typing', '_warnings', '_weakref', 'atexit', 'builtins', 'errno', 'faulthandler', 'gc', 'itertools', 'marshal', 'posix', 'pwd', 'sys', 'time')
sys.byteorder: little
sys.dont_write_bytecode: False
sys.executable: /usr/bin/python3.13
sys.filesystem_encoding: utf-8/surrogateescape
sys.flags: sys.flags(debug=0, inspect=0, interactive=0, optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0, ignore_environment=0, verbose=0, bytes_warning=0, quiet=0, hash_randomization=1, isolated=0, dev_mode=False, utf8_mode=0, warn_default_encoding=0, safe_path=False, int_max_str_digits=4300)
sys.float_info: sys.float_info(max=1.7976931348623157e+308, max_exp=1024, max_10_exp=308, min=2.2250738585072014e-308, min_exp=-1021, min_10_exp=-307, dig=15, mant_dig=53, epsilon=2.220446049250313e-16, radix=2, rounds=1)
sys.float_repr_style: short
sys.getrecursionlimit: 1000
sys.hash_info: sys.hash_info(width=64, modulus=2305843009213693951, inf=314159, nan=0, imag=1000003, algorithm='siphash13', hash_bits=64, seed_bits=128, cutoff=0)
sys.hexversion: 51183796
sys.implementation: namespace(name='cpython', cache_tag='cpython-313', version=sys.version_info(major=3, minor=13, micro=0, releaselevel='beta', serial=4), hexversion=51183796, _multiarch='x86_64-linux-gnu')
sys.int_info: sys.int_info(bits_per_digit=30, sizeof_digit=4, default_max_str_digits=4300, str_digits_check_threshold=640)
sys.maxsize: 9223372036854775807
sys.maxunicode: 1114111
sys.path: ['/var/str/python/selftest', '/usr/lib64/python313.zip', '/usr/lib64/python3.13', '/usr/lib64/python3.13/lib-dynload', '/usr/lib64/python3.13/site-packages', '/usr/lib/python3.13/site-packages']
sys.platform: linux
sys.platlibdir: lib64
sys.prefix: /usr
sys.stderr.encoding: utf-8/backslashreplace
sys.stdin.encoding: utf-8/strict
sys.stdout.encoding: utf-8/strict
sys.thread_info: sys.thread_info(name='pthread', lock='semaphore', version='NPTL 2.39.9000')
sys.version: 3.13.0b4 (main, Jul 19 2024, 00:00:00) [GCC 14.1.1 20240701 (Red Hat 14.1.1-7)]
sys.version_info: sys.version_info(major=3, minor=13, micro=0, releaselevel='beta', serial=4)
sysconfig.is_python_build: False
sysconfig[CCSHARED]: -fPIC
sysconfig[CC]: gcc
sysconfig[CFLAGSFORSHARED]: -fPIC
sysconfig[CFLAGS]: -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -fcf-protection -fexceptions -fcf-protection -fexceptions -fcf-protection -fexceptions -O3
sysconfig[CONFIG_ARGS]: '--build=x86_64-redhat-linux-gnu' '--host=x86_64-redhat-linux-gnu' '--program-prefix=' '--disable-dependency-tracking' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' '--includedir=/usr/include' '--libdir=/usr/lib64' '--libexecdir=/usr/libexec' '--localstatedir=/var' '--runstatedir=/run' '--sharedstatedir=/var/lib' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--with-platlibdir=lib64' '--enable-ipv6' '--enable-shared' '--with-computed-gotos=yes' '--with-dbmliborder=gdbm:ndbm:bdb' '--with-system-expat' '--with-system-ffi' '--with-system-libmpdec' '--enable-loadable-sqlite-extensions' '--with-dtrace' '--with-lto' '--with-ssl-default-suites=openssl' '--without-static-libpython' '--with-wheel-pkg-dir=/usr/share/python-wheels' '--with-valgrind' '--without-ensurepip' '--enable-experimental-jit=yes-off' '--enable-optimizations' 'build_alias=x86_64-redhat-linux-gnu' 'host_alias=x86_64-redhat-linux-gnu' 'PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig' 'CC=gcc' 'CFLAGS=-fcf-protection -fexceptions ' 'LDFLAGS= ' 'CPPFLAGS='
sysconfig[HOST_GNU_TYPE]: x86_64-redhat-linux-gnu
sysconfig[MACHDEP]: linux
sysconfig[MULTIARCH]: x86_64-linux-gnu
sysconfig[OPT]: -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -fcf-protection -fexceptions
sysconfig[PGO_PROF_USE_FLAG]: -fprofile-use -fprofile-correction
sysconfig[PY_CFLAGS]: -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -fcf-protection -fexceptions -fcf-protection -fexceptions -fcf-protection -fexceptions -O3
sysconfig[PY_CFLAGS_NODIST]: -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -D_GNU_SOURCE -fPIC -fwrapv -D_Py_TIER2=3 -D_Py_JIT -fno-semantic-interposition -flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none -g -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -D_GNU_SOURCE -fPIC -fwrapv -O3 -fprofile-use -fprofile-correction -I/builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/Include/internal -I/builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/Include/internal/mimalloc
sysconfig[PY_CORE_LDFLAGS]: -Wl,-z,relro -Wl,--as-needed -Wl,-z,pack-relative-relocs -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -specs=/usr/lib/rpm/redhat/redhat-package-notes -g -fno-semantic-interposition -flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none -g -Wl,-z,relro -Wl,--as-needed -Wl,-z,pack-relative-relocs -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -specs=/usr/lib/rpm/redhat/redhat-package-notes -g
sysconfig[PY_LDFLAGS_NODIST]: -Wl,-z,relro -Wl,--as-needed -Wl,-z,pack-relative-relocs -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -specs=/usr/lib/rpm/redhat/redhat-package-notes -g -fno-semantic-interposition -flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none -g -Wl,-z,relro -Wl,--as-needed -Wl,-z,pack-relative-relocs -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -Wl,--build-id=sha1 -specs=/usr/lib/rpm/redhat/redhat-package-notes -g
sysconfig[PY_STDMODULE_CFLAGS]: -fno-strict-overflow -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -fcf-protection -fexceptions -fcf-protection -fexceptions -fcf-protection -fexceptions -O3 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -D_GNU_SOURCE -fPIC -fwrapv -D_Py_TIER2=3 -D_Py_JIT -fno-semantic-interposition -flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none -g -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -march=x86-64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -mtls-dialect=gnu2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -D_GNU_SOURCE -fPIC -fwrapv -O3 -fprofile-use -fprofile-correction -I/builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/Include/internal -I/builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/Include/internal/mimalloc -IObjects -IInclude -IPython -I. -I/builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/Include -fPIC
sysconfig[Py_DEBUG]: 0
sysconfig[Py_ENABLE_SHARED]: 1
sysconfig[Py_GIL_DISABLED]: 0
sysconfig[SHELL]: /bin/sh -e
sysconfig[SOABI]: cpython-313-x86_64-linux-gnu
sysconfig[TEST_MODULES]: yes
sysconfig[abs_builddir]: /builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4/build/optimized
sysconfig[abs_srcdir]: /builddir/build/BUILD/python3.13-3.13.0_b4-build/Python-3.13.0b4
sysconfig[prefix]: /usr
sysconfig[srcdir]: /usr/lib64/python3.13/config-3.13-x86_64-linux-gnu
tempfile.gettempdir: /tmp
test_socket.HAVE_SOCKET_ALG: True
test_socket.HAVE_SOCKET_BLUETOOTH: False
test_socket.HAVE_SOCKET_CAN: False
test_socket.HAVE_SOCKET_CAN_ISOTP: False
test_socket.HAVE_SOCKET_CAN_J1939: False
test_socket.HAVE_SOCKET_HYPERV: False
test_socket.HAVE_SOCKET_QIPCRTR: True
test_socket.HAVE_SOCKET_RDS: False
test_socket.HAVE_SOCKET_UDPLITE: True
test_socket.HAVE_SOCKET_VSOCK: True
time.altzone: 0
time.daylight: 0
time.get_clock_info(monotonic): namespace(implementation='clock_gettime(CLOCK_MONOTONIC)', monotonic=True, adjustable=False, resolution=1e-09)
time.get_clock_info(perf_counter): namespace(implementation='clock_gettime(CLOCK_MONOTONIC)', monotonic=True, adjustable=False, resolution=1e-09)
time.get_clock_info(process_time): namespace(implementation='clock_gettime(CLOCK_PROCESS_CPUTIME_ID)', monotonic=True, adjustable=False, resolution=1e-09)
time.get_clock_info(thread_time): namespace(implementation='clock_gettime(CLOCK_THREAD_CPUTIME_ID)', monotonic=True, adjustable=False, resolution=1e-09)
time.get_clock_info(time): namespace(implementation='clock_gettime(CLOCK_REALTIME)', monotonic=False, adjustable=True, resolution=1e-09)
time.time: 1721664329.3427575
time.timezone: 0
time.tzname: ('UTC', 'UTC')
tkinter.TCL_VERSION: 8.6
tkinter.TK_VERSION: 8.6
tkinter.info_patchlevel: 8.6.14
zlib.ZLIB_RUNTIME_VERSION: 1.3.1.zlib-ng
zlib.ZLIB_VERSION: 1.3.1.zlib-ng

We invoke the installed tests like this:

python3.13 -m test -wW -j0 -i test_check_probes

I'd like to debug this and see if something is wrong with the test or perhaps in Fedora 41. But I don't know where to start.

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-122136: test_asyncio: Don't fail if the kernel buffers more data than advertised #123423
• [3.13] gh-122136: test_asyncio: Don't fail if the kernel buffers more data than advertised (GH-123423) #123443

[hroncok]

I wanted to cc @CendioOssman in the report but forgot.

[CendioOssman]

What the test tries to do is to fill the kernel socket buffers so that select() stops signalling that a send() is possible.

What we do to achieve this is set an explicit send and receive buffer size, to force the kernel to stop dynamically resizing them. We then ask the kernel what the real size is (since it will do funky stuff like double the requested size), and then write that much data in the buffer. The assertNotEqual() then checks that we've been forced to do some local buffering, as the kernel is full. If this hasn't happened, the test would otherwise give a false positive.

No idea why this isn't working in Fedora's CI. And it's difficult to debug if it only happens there. :/

Perhaps you do some creative fiddling with the network settings that forces dynamic buffer scaling to stay on?

Or is there some virtualization/containerization that results in the system lying to us?

[CendioOssman]

To debug, could you add some output of getsockopt(SO_SNDBUF), getsockopt(SO_RCVBUF), ioctl(SIOCINQ), and ioctl(SIOCOUTQ)?

[hroncok]

Thank you! The system is 100% virtualized/containerized. It runs on the Tetsing Farm and I don't know much about it, but perhaps @thrix might know what is happening or how to easily reproduce this locally.

[hroncok]

To debug, could you add some output of getsockopt(SO_SNDBUF), getsockopt(SO_RCVBUF), ioctl(SIOCINQ), and ioctl(SIOCOUTQ)?

Is this C? My Python has no socket.getsockopt, even thou it is documented at https://docs.python.org/3/library/socket.html#socket.socket.getsockopt

[hroncok]

Oh, I have getsockopt on socket objects, but it takes 2 arguments (level and option).

[hroncok]

So I can do something like his and run it on the CI (outputs from my machine):

>>> import socket
>>> s = socket.socket()
>>> s.getsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF)
16384
>>> s.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF)
131072

But for ioctl, I am out of my depth. I've tried something like fcntl.ioctl(s, termios.TIOCOUTQ) (as TIOCOUTQ is SIOCOUTQ in my /usr/include/linux/sockios.h), but I get OSError: [Errno 14] Bad address.

[mcepl]

We seem to have exactly the same here when packaging 3.13.0rc1 on openSUSE/Tumbleweed,
build log. Is it possible that the chrooted environment (which is what both us and Fedora have) misses something expected by this test?

[mgorny]

I'm also seeing this sometimes when testing on Gentoo amd64, in systemd-nspawn container. However, the test is only flaky here — generally it fails when the system is busy, but passes when Python's test suite has all the CPU to itself.

[hroncok]

This now started failing in the Fedora build system as well.