test_gdb now pass on ARM Raspbian 3.x. I'm not sure why test_gdb fails on 3.10 but pass on 3.x.

For me, it looks more like a gcc or gdb issue, rather than a Python bug.

ARM Raspbian 3.10:
https://buildbot.python.org/all/#/builders/685/builds/76

test.pythoninfo:

CC.version: gcc (Raspbian 10.2.1-6+rpi1) 10.2.1 20210110
gdb_version: GNU gdb (Raspbian 10.1-1.7) 10.1.90.20210103-git

sysconfig[CCSHARED]: -fPIC
sysconfig[CC]: gcc -pthread
sysconfig[CFLAGS]: -Wno-unused-result -Wsign-compare -g -Og -Wall
sysconfig[CONFIG_ARGS]: '--prefix' '/var/lib/buildbot/workers/3.10.gps-raspbian/build/target' '--with-pydebug'
sysconfig[HOST_GNU_TYPE]: armv7l-unknown-linux-gnueabihf
sysconfig[MACHDEP]: linux
sysconfig[MULTIARCH]: arm-linux-gnueabihf
sysconfig[OPT]: -g -Og -Wall
sysconfig[PY_CFLAGS]: -Wno-unused-result -Wsign-compare -g -Og -Wall
sysconfig[PY_CFLAGS_NODIST]: -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal
sysconfig[PY_STDMODULE_CFLAGS]: -Wno-unused-result -Wsign-compare -g -Og -Wall -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -I. -I./Include
sysconfig[Py_DEBUG]: 1

Logs:

======================================================================
FAIL: test_bt (test.test_gdb.PyBtTests)
Verify that the "py-bt" command works
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/var/lib/buildbot/workers/3.10.gps-raspbian/build/Lib/test/test_gdb.py", line 776, in test_bt
    self.assertMultilineMatches(bt,
  File "/var/lib/buildbot/workers/3.10.gps-raspbian/build/Lib/test/test_gdb.py", line 295, in assertMultilineMatches
    self.fail(msg='%r did not match %r' % (actual, pattern))
AssertionError: 'Breakpoint 1 at 0x258ba4: file Python/bltinmodule.c, line 1194.\n[Thread debugging using libthread_db enabled]\nUsing host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".\n\nBreakpoint 1, builtin_id (self=, v=42) at Python/bltinmodule.c:1194\n1194\t{\nTraceback (most recent call first):\n  <built-in method id of module object at remote 0xb68b8360>\n' did not match '^.*\nTraceback \\(most recent call first\\):\n  <built-in method id of module object .*>\n  File ".*gdb_sample.py", line 10, in baz\n    id\\(42\\)\n  File ".*gdb_sample.py", line 7, in bar\n    baz\\(a, b, c\\)\n  File ".*gdb_sample.py", line 4, in foo\n    bar\\(a, b, c\\)\n  File ".*gdb_sample.py", line 12, in <module>\n    foo\\(1, 2, 3\\)\n'

Stderr:
Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0xfdfdfd83: 
Error occurred in Python: Cannot access memory at address 0xfdfdfd83