From e05d202ebf0904cf0a980fde76f4a38bb8dc7c3b Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Tue, 16 Apr 2024 22:05:12 +0200 Subject: gh-117755: Remove tests on huge memory allocations (#117938) Remove unreliable tests on huge memory allocations: * Remove test_maxcontext_exact_arith() of test_decimal. Stefan Krah, test author, agreed on removing the test: https://github.com/python/cpython/issues/114331#issuecomment-1925731273 * Remove test_constructor() tests of test_io. Sam Gross suggests remove them: https://github.com/python/cpython/pull/117809#pullrequestreview-2003889558 On Linux, depending how overcommit is configured, especially on Linux s390x, a huge memory allocation (half or more of the full address space) can succeed, but then the process will eat the full system swap and make the system slower and slower until the whole system becomes unusable. Moreover, these tests had to be skipped when Python is built with sanitizers. --- Lib/test/test_decimal.py | 48 +-------------------------------------------- Lib/test/test_io.py | 51 +----------------------------------------------- 2 files changed, 2 insertions(+), 97 deletions(-) diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py index 05dcb25..7010c34 100644 --- a/Lib/test/test_decimal.py +++ b/Lib/test/test_decimal.py @@ -34,12 +34,10 @@ import numbers import locale from test.support import (is_resource_enabled, requires_IEEE_754, requires_docstrings, - check_sanitizer, check_disallow_instantiation) from test.support import (TestFailed, run_with_locale, cpython_only, - darwin_malloc_err_warning, is_emscripten, - skip_on_s390x) + darwin_malloc_err_warning) from test.support.import_helper import import_fresh_module from test.support import threading_helper from test.support import warnings_helper @@ -5644,50 +5642,6 @@ class CWhitebox(unittest.TestCase): self.assertEqual(Decimal.from_float(cls(101.1)), Decimal.from_float(101.1)) - # Issue 41540: - @unittest.skipIf(sys.platform.startswith("aix"), - "AIX: default ulimit: test is flaky because of extreme over-allocation") - @unittest.skipIf(is_emscripten, "Test is unstable on Emscripten") - @unittest.skipIf(check_sanitizer(address=True, memory=True), - "ASAN/MSAN sanitizer defaults to crashing " - "instead of returning NULL for malloc failure.") - # gh-114331: The test allocates 784 271 641 GiB and mimalloc does not fail - # to allocate it when using mimalloc on s390x. - @skip_on_s390x - def test_maxcontext_exact_arith(self): - - # Make sure that exact operations do not raise MemoryError due - # to huge intermediate values when the context precision is very - # large. - - # The following functions fill the available precision and are - # therefore not suitable for large precisions (by design of the - # specification). - MaxContextSkip = ['logical_invert', 'next_minus', 'next_plus', - 'logical_and', 'logical_or', 'logical_xor', - 'next_toward', 'rotate', 'shift'] - - Decimal = C.Decimal - Context = C.Context - localcontext = C.localcontext - - # Here only some functions that are likely candidates for triggering a - # MemoryError are tested. deccheck.py has an exhaustive test. - maxcontext = Context(prec=C.MAX_PREC, Emin=C.MIN_EMIN, Emax=C.MAX_EMAX) - with localcontext(maxcontext): - self.assertEqual(Decimal(0).exp(), 1) - self.assertEqual(Decimal(1).ln(), 0) - self.assertEqual(Decimal(1).log10(), 0) - self.assertEqual(Decimal(10**2).log10(), 2) - self.assertEqual(Decimal(10**223).log10(), 223) - self.assertEqual(Decimal(10**19).logb(), 19) - self.assertEqual(Decimal(4).sqrt(), 2) - self.assertEqual(Decimal("40E9").sqrt(), Decimal('2.0E+5')) - self.assertEqual(divmod(Decimal(10), 3), (3, 1)) - self.assertEqual(Decimal(10) // 3, 3) - self.assertEqual(Decimal(4) / 2, 2) - self.assertEqual(Decimal(400) ** -1, Decimal('0.0025')) - def test_c_immutable_types(self): SignalDict = type(C.Context().flags) SignalDictMixin = SignalDict.__bases__[0] diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py index c3dc057..e5cb08c 100644 --- a/Lib/test/test_io.py +++ b/Lib/test/test_io.py @@ -40,8 +40,7 @@ from test import support from test.support.script_helper import ( assert_python_ok, assert_python_failure, run_python_until_end) from test.support import ( - import_helper, is_apple, os_helper, skip_if_sanitizer, threading_helper, warnings_helper, - skip_on_s390x + import_helper, is_apple, os_helper, threading_helper, warnings_helper, ) from test.support.os_helper import FakePath @@ -1698,22 +1697,6 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests): class CBufferedReaderTest(BufferedReaderTest, SizeofTest): tp = io.BufferedReader - @skip_if_sanitizer(memory=True, address=True, thread=True, - reason="sanitizer defaults to crashing " - "instead of returning NULL for malloc failure.") - # gh-117755: The test allocates 9 223 372 036 854 775 807 bytes - # (0x7fffffffffffffff) and mimalloc fails with a division by zero on s390x. - @skip_on_s390x - def test_constructor(self): - BufferedReaderTest.test_constructor(self) - # The allocation can succeed on 32-bit builds, e.g. with more - # than 2 GiB RAM and a 64-bit kernel. - if sys.maxsize > 0x7FFFFFFF: - rawio = self.MockRawIO() - bufio = self.tp(rawio) - self.assertRaises((OverflowError, MemoryError, ValueError), - bufio.__init__, rawio, sys.maxsize) - def test_initialization(self): rawio = self.MockRawIO([b"abc"]) bufio = self.tp(rawio) @@ -2069,22 +2052,6 @@ class BufferedWriterTest(unittest.TestCase, CommonBufferedTests): class CBufferedWriterTest(BufferedWriterTest, SizeofTest): tp = io.BufferedWriter - @skip_if_sanitizer(memory=True, address=True, thread=True, - reason="sanitizer defaults to crashing " - "instead of returning NULL for malloc failure.") - # gh-117755: The test allocates 9 223 372 036 854 775 807 bytes - # (0x7fffffffffffffff) and mimalloc fails with a division by zero on s390x. - @skip_on_s390x - def test_constructor(self): - BufferedWriterTest.test_constructor(self) - # The allocation can succeed on 32-bit builds, e.g. with more - # than 2 GiB RAM and a 64-bit kernel. - if sys.maxsize > 0x7FFFFFFF: - rawio = self.MockRawIO() - bufio = self.tp(rawio) - self.assertRaises((OverflowError, MemoryError, ValueError), - bufio.__init__, rawio, sys.maxsize) - def test_initialization(self): rawio = self.MockRawIO() bufio = self.tp(rawio) @@ -2594,22 +2561,6 @@ class BufferedRandomTest(BufferedReaderTest, BufferedWriterTest): class CBufferedRandomTest(BufferedRandomTest, SizeofTest): tp = io.BufferedRandom - @skip_if_sanitizer(memory=True, address=True, thread=True, - reason="sanitizer defaults to crashing " - "instead of returning NULL for malloc failure.") - # gh-117755: The test allocates 9 223 372 036 854 775 807 bytes - # (0x7fffffffffffffff) and mimalloc fails with a division by zero on s390x. - @skip_on_s390x - def test_constructor(self): - BufferedRandomTest.test_constructor(self) - # The allocation can succeed on 32-bit builds, e.g. with more - # than 2 GiB RAM and a 64-bit kernel. - if sys.maxsize > 0x7FFFFFFF: - rawio = self.MockRawIO() - bufio = self.tp(rawio) - self.assertRaises((OverflowError, MemoryError, ValueError), - bufio.__init__, rawio, sys.maxsize) - def test_garbage_collection(self): CBufferedReaderTest.test_garbage_collection(self) CBufferedWriterTest.test_garbage_collection(self) -- cgit v0.12