Bug: Debug Attach stopped working in 2025.18.0

提供された起動構成、Python 3.12 プロセス、SLES 15-SP4 環境、および host gdb を使って attach の失敗を再現します。debugpy/server/cli.py、pydevd_attach_to_process/add_code_to_python_process.py、および attach_linux_amd64.so に関連する traceback を読みます。完了条件は、報告された injection エラーなしで 2025.18.0 で PID attach が機能することです。

Debug attach mode stopped working in 2025.18.0. When I downgrade to 2025.16.0, it works again.

Reproducer:

Launch configuration:

{
    "name": "Python Debugger: Attach using Process Id",
    "type": "debugpy",
    "request": "attach",
    "processId": "${command:pickProcess}"
}

In my SLES 15-SP4 (Linux) machine:

> python3
Python 3.12.0 (main, Oct 18 2023, 17:19:09) [GCC 7.5.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
Ctrl click to launch VS Code Native REPL
>>> import os
>>> os.getpid()
<pid of python process will be shown>

Start the debugging with the launch configuration from above and use the pid from the os.getpid(). Then observe that it will just try to attach for a minute, then give up with the following error:

This is the content in the debug console:

Attach to PID failed.

--- Starting attach to pid: 141427 ---
0.00s - Debugger warning: It seems that frozen modules are being used, which may
0.00s - make the debugger miss breakpoints. Please pass -Xfrozen_modules=off
0.00s - to python to disable frozen modules.
0.00s - Note: Debugging will proceed. Set PYDEVD_DISABLE_FILE_VALIDATION=1 to disable this validation.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007fa0655600a6 in select () from /lib64/libc.so.6
The target architecture is set to "auto" (currently "i386:x86-64").
$1 = (void *) 0x0
No symbol "DoAttach" in current context.
[Inferior 1 (process 141427) detached]
E+00000.426: Code injection into PID=141427 failed:
             
             Traceback (most recent call last):
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 468, in attach_to_pid
                 add_code_to_python_process.run_python_code(
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/_vendored/pydevd/pydevd_attach_to_process/add_code_to_python_process.py", line 483, in run_python_code_linux
                 subprocess.check_call(" ".join(cmd), shell=True, env=env)
               File "/usr/itm/python/3.12.0/lib/python3.12/subprocess.py", line 413, in check_call
                 raise CalledProcessError(retcode, cmd)
             subprocess.CalledProcessError: Command 'gdb --nw --nh --nx --pid 141427 --batch --eval-command='set scheduler-locking off' --eval-command='set architecture auto' --eval-command='call (void*)dlopen("/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/_vendored/pydevd/pydevd_attach_to_process/attach_linux_amd64.so", 2)' --eval-command='sharedlibrary attach_linux_amd64' --eval-command='call (int)DoAttach(0, "import codecs;import json;import sys;decode = lambda s: codecs.utf_8_decode(bytearray(s))[0] if s is not None else None;script_dir = decode([47, 100, 105, 115, 107, 50, 47, 116, 115, 111, 110, 111, 110, 111, 47, 46, 118, 115, 99, 111, 100, 101, 45, 115, 101, 114, 118, 101, 114, 47, 101, 120, 116, 101, 110, 115, 105, 111, 110, 115, 47, 109, 115, 45, 112, 121, 116, 104, 111, 110, 46, 100, 101, 98, 117, 103, 112, 121, 45, 50, 48, 50, 53, 46, 49, 56, 46, 48, 47, 98, 117, 110, 100, 108, 101, 100, 47, 108, 105, 98, 115, 47, 100, 101, 98, 117, 103, 112, 121, 47, 97, 100, 97, 112, 116, 101, 114, 47, 46, 46, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 115, 101, 114, 118, 101, 114]);setup = json.loads(decode([123, 34, 109, 111, 100, 101, 34, 58, 32, 34, 99, 111, 110, 110, 101, 99, 116, 34, 44, 32, 34, 97, 100, 100, 114, 101, 115, 115, 34, 58, 32, 91, 34, 49, 50, 55, 46, 48, 46, 48, 46, 49, 34, 44, 32, 52, 52, 52, 56, 57, 93, 44, 32, 34, 119, 97, 105, 116, 95, 102, 111, 114, 95, 99, 108, 105, 101, 110, 116, 34, 58, 32, 102, 97, 108, 115, 101, 44, 32, 34, 108, 111, 103, 95, 116, 111, 34, 58, 32, 110, 117, 108, 108, 44, 32, 34, 97, 100, 97, 112, 116, 101, 114, 95, 97, 99, 99, 101, 115, 115, 95, 116, 111, 107, 101, 110, 34, 58, 32, 34, 97, 53, 101, 51, 51, 100, 52, 53, 50, 48, 56, 50, 51, 48, 49, 54, 53, 54, 48, 55, 57, 52, 52, 48, 57, 54, 57, 98, 48, 51, 52, 52, 102, 99, 99, 50, 56, 97, 54, 98, 57, 53, 55, 49, 55, 50, 50, 99, 54, 97, 99, 100, 48, 53, 48, 49, 54, 102, 102, 50, 99, 54, 102, 102, 34, 125]));sys.path.insert(0, script_dir);import attach_pid_injected;del sys.path[0];attach_pid_injected.attach(setup);", 0)'' returned non-zero exit status 1.
             
             Stack where logged:
               File "<frozen runpy>", line 198, in _run_module_as_main
               File "<frozen runpy>", line 88, in _run_code
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/__main__.py", line 71, in <module>
                 cli.main()
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 508, in main
                 run()
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 475, in attach_to_pid
                 log.reraise_exception("Code injection into PID={0} failed:", pid)
               File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/common/log.py", line 222, in reraise_exception
                 _exception(format_string, *args, **kwargs)
             

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/__main__.py", line 71, in <module>
    cli.main()
  File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 508, in main
    run()
  File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 475, in attach_to_pid
    log.reraise_exception("Code injection into PID={0} failed:", pid)
  File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/adapter/../../debugpy/../debugpy/server/cli.py", line 468, in attach_to_pid
    add_code_to_python_process.run_python_code(
  File "/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/_vendored/pydevd/pydevd_attach_to_process/add_code_to_python_process.py", line 483, in run_python_code_linux
    subprocess.check_call(" ".join(cmd), shell=True, env=env)
  File "/usr/itm/python/3.12.0/lib/python3.12/subprocess.py", line 413, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command 'gdb --nw --nh --nx --pid 141427 --batch --eval-command='set scheduler-locking off' --eval-command='set architecture auto' --eval-command='call (void*)dlopen("/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/_vendored/pydevd/pydevd_attach_to_process/attach_linux_amd64.so", 2)' --eval-command='sharedlibrary attach_linux_amd64' --eval-command='call (int)DoAttach(0, "import codecs;import json;import sys;decode = lambda s: codecs.utf_8_decode(bytearray(s))[0] if s is not None else None;script_dir = decode([47, 100, 105, 115, 107, 50, 47, 116, 115, 111, 110, 111, 110, 111, 47, 46, 118, 115, 99, 111, 100, 101, 45, 115, 101, 114, 118, 101, 114, 47, 101, 120, 116, 101, 110, 115, 105, 111, 110, 115, 47, 109, 115, 45, 112, 121, 116, 104, 111, 110, 46, 100, 101, 98, 117, 103, 112, 121, 45, 50, 48, 50, 53, 46, 49, 56, 46, 48, 47, 98, 117, 110, 100, 108, 101, 100, 47, 108, 105, 98, 115, 47, 100, 101, 98, 117, 103, 112, 121, 47, 97, 100, 97, 112, 116, 101, 114, 47, 46, 46, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 115, 101, 114, 118, 101, 114]);setup = json.loads(decode([123, 34, 109, 111, 100, 101, 34, 58, 32, 34, 99, 111, 110, 110, 101, 99, 116, 34, 44, 32, 34, 97, 100, 100, 114, 101, 115, 115, 34, 58, 32, 91, 34, 49, 50, 55, 46, 48, 46, 48, 46, 49, 34, 44, 32, 52, 52, 52, 56, 57, 93, 44, 32, 34, 119, 97, 105, 116, 95, 102, 111, 114, 95, 99, 108, 105, 101, 110, 116, 34, 58, 32, 102, 97, 108, 115, 101, 44, 32, 34, 108, 111, 103, 95, 116, 111, 34, 58, 32, 110, 117, 108, 108, 44, 32, 34, 97, 100, 97, 112, 116, 101, 114, 95, 97, 99, 99, 101, 115, 115, 95, 116, 111, 107, 101, 110, 34, 58, 32, 34, 97, 53, 101, 51, 51, 100, 52, 53, 50, 48, 56, 50, 51, 48, 49, 54, 53, 54, 48, 55, 57, 52, 52, 48, 57, 54, 57, 98, 48, 51, 52, 52, 102, 99, 99, 50, 56, 97, 54, 98, 57, 53, 55, 49, 55, 50, 50, 99, 54, 97, 99, 100, 48, 53, 48, 49, 54, 102, 102, 50, 99, 54, 102, 102, 34, 125]));sys.path.insert(0, script_dir);import attach_pid_injected;del sys.path[0];attach_pid_injected.attach(setup);", 0)'' returned non-zero exit status 1.
PYDEVD_GDB_SCAN_SHARED_LIBRARIES not set (scanning all libraries for needed symbols).
Running: gdb --nw --nh --nx --pid 141427 --batch --eval-command='set scheduler-locking off' --eval-command='set architecture auto' --eval-command='call (void*)dlopen("/disk2/tsonono/.vscode-server/extensions/ms-python.debugpy-2025.18.0/bundled/libs/debugpy/_vendored/pydevd/pydevd_attach_to_process/attach_linux_amd64.so", 2)' --eval-command='sharedlibrary attach_linux_amd64' --eval-command='call (int)DoAttach(0, "import codecs;import json;import sys;decode = lambda s: codecs.utf_8_decode(bytearray(s))[0] if s is not None else None;script_dir = decode([47, 100, 105, 115, 107, 50, 47, 116, 115, 111, 110, 111, 110, 111, 47, 46, 118, 115, 99, 111, 100, 101, 45, 115, 101, 114, 118, 101, 114, 47, 101, 120, 116, 101, 110, 115, 105, 111, 110, 115, 47, 109, 115, 45, 112, 121, 116, 104, 111, 110, 46, 100, 101, 98, 117, 103, 112, 121, 45, 50, 48, 50, 53, 46, 49, 56, 46, 48, 47, 98, 117, 110, 100, 108, 101, 100, 47, 108, 105, 98, 115, 47, 100, 101, 98, 117, 103, 112, 121, 47, 97, 100, 97, 112, 116, 101, 114, 47, 46, 46, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 46, 46, 47, 100, 101, 98, 117, 103, 112, 121, 47, 115, 101, 114, 118, 101, 114]);setup = json.loads(decode([123, 34, 109, 111, 100, 101, 34, 58, 32, 34, 99, 111, 110, 110, 101, 99, 116, 34, 44, 32, 34, 97, 100, 100, 114, 101, 115, 115, 34, 58, 32, 91, 34, 49, 50, 55, 46, 48, 46, 48, 46, 49, 34, 44, 32, 52, 52, 52, 56, 57, 93, 44, 32, 34, 119, 97, 105, 116, 95, 102, 111, 114, 95, 99, 108, 105, 101, 110, 116, 34, 58, 32, 102, 97, 108, 115, 101, 44, 32, 34, 108, 111, 103, 95, 116, 111, 34, 58, 32, 110, 117, 108, 108, 44, 32, 34, 97, 100, 97, 112, 116, 101, 114, 95, 97, 99, 99, 101, 115, 115, 95, 116, 111, 107, 101, 110, 34, 58, 32, 34, 97, 53, 101, 51, 51, 100, 52, 53, 50, 48, 56, 50, 51, 48, 49, 54, 53, 54, 48, 55, 57, 52, 52, 48, 57, 54, 57, 98, 48, 51, 52, 52, 102, 99, 99, 50, 56, 97, 54, 98, 57, 53, 55, 49, 55, 50, 50, 99, 54, 97, 99, 100, 48, 53, 48, 49, 54, 102, 102, 50, 99, 54, 102, 102, 34, 125]));sys.path.insert(0, script_dir);import attach_pid_injected;del sys.path[0];attach_pid_injected.attach(setup);", 0)'

The gdb version on my host if 14.2, if that's of any relevance, as the debugger is seemingly using the host's gdb based on the output in the debug console.