Misc. Buck ASAN fixes

Summary: Grab-bag of fixes for ASAN in Python tests under Buck. The biggest change which takes up most of this diff is updating `mini_configure.py` to make changes to `CFLAGS` in the sysconfig data so test libraries can detect sanitizers are enabled.

Reviewed By: alexmalyshev

Differential Revision: D56221781

fbshipit-source-id: f38c4dbc38008edc930f70fc2745b8afbb59f6fa

Lib/test/cinder_support.py

@@ -1,5 +1,6 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 
+import ctypes
 import multiprocessing
 import sys
 import tempfile
@@ -102,9 +103,17 @@ def wrapper(*args):
     return func
 
 
-# This is pretty long because ASAN + JIT + subprocess + the Python compiler can
-# be pretty slow in CI.
-SUBPROCESS_TIMEOUT_SEC = 5
+def is_asan_build():
+    try:
+        ctypes.pythonapi.__asan_init
+        return True
+    except AttributeError:
+        return False
+
+
+# This is long because ASAN + JIT + subprocess + the Python compiler can be
+# pretty slow in CI.
+SUBPROCESS_TIMEOUT_SEC = 100 if is_asan_build() else 5
 
 
 @contextmanager

cinderx/TestScripts/asan_skip_tests.txt

@@ -5,3 +5,8 @@ test_wait3
 test_logging
 # Monkey patching in cinder_test_runner.py for ASAN breaks this
 test.test_trace.TestCoverage.test_coverage_ignore
+
+# These get segfaults in the sub-processes they start. I didn't look at the
+# details but my guess is thread memory stack size limits. With ASAN we need a
+# bigger default thread stack-size (as set in cinder_test_runner.py).
+test.test_multiprocessing_main_handling.SpawnCmdLineTest

cinderx/TestScripts/cinder_test_runner.py

@@ -40,6 +40,7 @@
 from pathlib import Path
 
 from test import support
+from test.cinder_support import is_asan_build
 from test.support import os_helper
 from test.libregrtest.cmdline import Namespace
 from test.libregrtest.main import Regrtest
@@ -950,9 +951,14 @@ def replay_main(args):
     # runaway loops. This 8GiB number is arbitrary but seems to be enough at
     # the time of writing.
     mem_limit_default = (
-        8192 * 1024 * 1024 if os.environ.get('ASAN_OPTIONS') is None else -1
+        -1 if is_asan_build() else 8192 * 1024 * 1024
     )
 
+    # Increase default stack size for threads in ASAN builds as this can use
+    # a lot more stack space.
+    if is_asan_build():
+        threading.stack_size(1024 * 1024 * 10)
+
     parser.add_argument(
         "--memory-limit",
         type=int,