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memory leak in _PyBytes_FormatEx error path #140939
Description
Bug report
Bug description:
import unittest
class BaseBytesTest:
def test_mod(self):
def check(fmt, vals, result):
bf = self.type2test(fmt)
bf = bf % vals
check(b'%*b', (2**63-1, b'abc'), b' abc')
class ByteArrayTest(BaseBytesTest, unittest.TestCase):
type2test = bytearray
if __name__ == "__main__":
unittest.main()=================================================================
==776798==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 60 byte(s) in 1 object(s) allocated from:
#0 0x7a4877a6d9c7 in malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:69
#1 0x55e03c01bdf1 in _PyMem_RawMalloc ../Objects/obmalloc.c:63
#2 0x55e03c01b1c2 in _PyMem_DebugRawAlloc ../Objects/obmalloc.c:2887
#3 0x55e03c01b22a in _PyMem_DebugRawMalloc ../Objects/obmalloc.c:2920
#4 0x55e03c01caa8 in _PyMem_DebugMalloc ../Objects/obmalloc.c:3085
#5 0x55e03c045a95 in PyObject_Malloc ../Objects/obmalloc.c:1493
#6 0x55e03bf3d755 in _PyBytes_FromSize ../Objects/bytesobject.c:126
#7 0x55e03bf42690 in PyBytes_FromStringAndSize ../Objects/bytesobject.c:156
#8 0x55e03bf0bf70 in _PyPegen_parse_string ../Parser/string_parser.c:334
#9 0x55e03bdf6370 in _PyPegen_constant_from_string ../Parser/action_helpers.c:1451
#10 0x55e03be12662 in string_rule ../Parser/parser.c:17153
#11 0x55e03be55755 in _tmp_154_rule ../Parser/parser.c:37189
#12 0x55e03be55e08 in _loop1_80_rule ../Parser/parser.c:32749
#13 0x55e03be5eede in strings_rule ../Parser/parser.c:17224
#14 0x55e03be2f755 in atom_rule ../Parser/parser.c:15165
#15 0x55e03be31f78 in primary_raw ../Parser/parser.c:14803
#16 0x55e03be325a4 in primary_rule ../Parser/parser.c:14601
#17 0x55e03be32f62 in await_primary_rule ../Parser/parser.c:14555
#18 0x55e03be3351f in power_rule ../Parser/parser.c:14431
#19 0x55e03be350b7 in factor_rule ../Parser/parser.c:14381
#20 0x55e03be377b7 in term_raw ../Parser/parser.c:14222
#21 0x55e03be37de3 in term_rule ../Parser/parser.c:13965
#22 0x55e03be38aa7 in sum_raw ../Parser/parser.c:13918
#23 0x55e03be39106 in sum_rule ../Parser/parser.c:13797
#24 0x55e03be3a72f in shift_expr_raw ../Parser/parser.c:13757
#25 0x55e03be3ad5b in shift_expr_rule ../Parser/parser.c:13617
#26 0x55e03be3b55e in bitwise_and_raw ../Parser/parser.c:13577
#27 0x55e03be3bbbd in bitwise_and_rule ../Parser/parser.c:13495
#28 0x55e03be3c3c0 in bitwise_xor_raw ../Parser/parser.c:13455
#29 0x55e03be3ca1f in bitwise_xor_rule ../Parser/parser.c:13373
SUMMARY: AddressSanitizer: 60 byte(s) leaked in 1 allocation(s).
CPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Activity
Hullaah commentedon Nov 3, 2025
Hi. I'm new here and would love to contribute to python and take this as my first issue. How can I reproduce the bug?
YuanchengJiang commentedon Nov 3, 2025
Hi, you could build the main branch executable with address sanitizer
--with-address-sanitizer.Hullaah commentedon Nov 3, 2025
Oh okay I made some research and actually built with
./configure --with-address-sanitizer --with-pydebug --without-pymallocgh-140939: Fix memory leak in `_PyBytes_FormatEx` error path (#140957)
[-]memory leak in `_PyPegen_constant_from_string`[/-][+]memory leak in `_PyBytes_FormatEx` error path[/+][3.14] pythongh-140939: Fix memory leak in `_PyBytes_FormatEx` error …
[3.13] pythongh-140939: Fix memory leak in `_PyBytes_FormatEx` error …
[3.13] gh-140939: Fix memory leak in `_PyBytes_FormatEx` error path (G…
[3.14] gh-140939: Fix memory leak in `_PyBytes_FormatEx` error path (G…
pythongh-140939: Fix memory leak in `_PyBytes_FormatEx` error path (p…