test_compile and test_multiprocessing_forkserver crashed with segfault (SIGSEGV) on AMD64 Ubuntu 3.x:
https://buildbot.python.org/all/#/builders/708/builds/31

It *seems* like test_compile.test_stack_overflow() crashed, but the log is not reliable so I cannot confirm.

According to buildbot, the responsible change is:
"bpo-43693: Un-revert commit f3fa63e. (#26609)(10 hours ago)"
https://github.com/python/cpython/commit/3e1c7167d86a2a928cdcb659094aa10bb5550c4c

So Eric, can you please investigate the change? If nobody is available to fix the buildbot, I suggest to revert the change.


Python was built in debug mode with:

./configure --prefix '$(PWD)/target' --with-pydebug
make all


test.pythoninfo:

CC.version: gcc (Ubuntu 10.3.0-1ubuntu1) 10.3.0
os.uname: posix.uname_result(sysname='Linux', nodename='doxy.learntosolveit.com', release='5.11.0-18-generic', version='#19-Ubuntu SMP Fri May 7 14:22:03 UTC 2021', machine='x86_64')
platform.platform: Linux-5.11.0-18-generic-x86_64-with-glibc2.33
sys.thread_info: sys.thread_info(name='pthread', lock='semaphore', version='NPTL 2.33')


Logs:

./python  ./Tools/scripts/run_tests.py -j 1 -u all -W --slowest --fail-env-changed --timeout=900 -j2 --junit-xml test-results.xml 
== CPython 3.11.0a0 (heads/main:3e1c7167d8, Jun 8 2021, 22:09:42) [GCC 10.3.0]
== Linux-5.11.0-18-generic-x86_64-with-glibc2.33 little-endian
== cwd: /home/buildbot/buildarea/3.x.skumaran-ubuntu-x86_64/build/build/test_python_1439770æ
== CPU count: 1
== encodings: locale=UTF-8, FS=utf-8
Using random seed 5059550
0:00:00 load avg: 0.97 Run tests in parallel using 2 child processes (timeout: 15 min, worker timeout: 20 min)
(...)
0:00:43 load avg: 2.22 running: test_compile (34.7 sec), test_signal (30.8 sec)
0:01:12 load avg: 3.84 [ 13/427/1] test_compile crashed (Exit code -9) -- running: test_signal (59.6 sec)
(...)
0:06:26 load avg: 1.84 running: test_concurrent_futures (42.0 sec), test_multiprocessing_forkserver (30.0 sec)
0:06:56 load avg: 3.91 running: test_concurrent_futures (1 min 12 sec), test_multiprocessing_forkserver (1 min)
0:07:26 load avg: 5.47 running: test_concurrent_futures (1 min 42 sec), test_multiprocessing_forkserver (1 min 30 sec)
0:07:58 load avg: 5.93 running: test_concurrent_futures (2 min 13 sec), test_multiprocessing_forkserver (2 min 2 sec)
0:08:30 load avg: 5.73 running: test_concurrent_futures (2 min 44 sec), test_multiprocessing_forkserver (2 min 33 sec)
0:08:48 load avg: 4.62 [ 85/427/2] test_multiprocessing_forkserver crashed (Exit code -9) -- running: test_concurrent_futures (3 min 3 sec)
(...)
2 tests failed:
    test_compile test_multiprocessing_forkserver
(...)
0:27:56 load avg: 1.28 Re-running test_compile in verbose mode
test_and (test.test_compile.TestExpressionStackSize) ... ok
(...)
test_sequence_unpacking_error (test.test_compile.TestSpecifics) ... ok
test_single_statement (test.test_compile.TestSpecifics) ... ok
test_stack_overflow (test.test_compile.TestSpecifics) ... 
make: *** [Makefile:1256: buildbottest] Killed
program finished with exit code 2
elapsedTime=1684.973552