[Windows]: process_iter will sometimes return a WindowsError: The operation completed successfully: (originated from NtWow64ReadVirtualMemory64)

[dusans]

Windows

• Windows 10 1909 (64 bit) (OS Build 18363.1082)
• psutil version: 5.6.3
• Python 2.7 32 bit

Bug description
psutil.process_iter will sometimes return a WindowsError.

Test script

import os
import psutil


def get_pids(name, cmdline_param=None):
    "Return a list of processes pids matching 'name'."
    ls = []
    for p in psutil.process_iter(attrs=["name", "exe", "cmdline"]):
        if (name == p.info['name']
                or p.info['exe'] and os.path.basename(p.info['exe']) == name
                or p.info['cmdline'] and p.info['cmdline'][0] == name):
            if (cmdline_param is None
                    or p.info['cmdline'] and cmdline_param in " ".join(p.info['cmdline'])):
                ls.append(p.pid)
    return ls


for i in range(10000):
    print i, get_pids("some_gui.exe")
    print i, get_pids("pythonw.exe", "some_gui.pyw")

Traceback

2294 []
2294 []
2295

Traceback (most recent call last):
  File "test_get_pids.py", line 19, in <module>
    print i, get_pids("some_gui.exe")
  File "test_get_pids.py", line 8, in get_pids
    for p in psutil.process_iter(attrs=["name", "exe", "cmdline"]):
  File "lib\site-packages\psutil\__init__.py", line 1566, in process_iter
    yield add(pid)
  File "lib\site-packages\psutil\__init__.py", line 1543, in add
    proc.info = proc.as_dict(attrs=attrs, ad_value=ad_value)
  File "lib\site-packages\psutil\__init__.py", line 638, in as_dict
    ret = meth()
  File "lib\site-packages\psutil\__init__.py", line 790, in cmdline
    return self._proc.cmdline()
  File "lib\site-packages\psutil\_pswindows.py", line 718, in wrapper
    raise convert_oserror(err, pid=self.pid, name=self._name)
  File "lib\site-packages\psutil\_pswindows.py", line 708, in convert_oserror
    raise exc
WindowsError: [Error 0] The operation completed successfully: '(originated from NtWow64ReadVirtualMemory64)'

Traceback (most recent call last):
  File "test_get_pids.py", line 19, in <module>
    print i, get_pids("some_gui.exe")
  File "test_get_pids.py", line 8, in get_pids
    for p in psutil.process_iter(attrs=["name", "exe", "cmdline"]):
  File "lib\site-packages\psutil\__init__.py", line 1566, in process_iter
    yield add(pid)
  File "lib\site-packages\psutil\__init__.py", line 1543, in add
    proc.info = proc.as_dict(attrs=attrs, ad_value=ad_value)
  File "lib\site-packages\psutil\__init__.py", line 638, in as_dict
    ret = meth()
  File "lib\site-packages\psutil\__init__.py", line 790, in cmdline
    return self._proc.cmdline()
  File "lib\site-packages\psutil\_pswindows.py", line 718, in wrapper
    raise convert_oserror(err, pid=self.pid, name=self._name)
  File "lib\site-packages\psutil\_pswindows.py", line 708, in convert_oserror
    raise exc
WindowsError: [Error 998] Invalid access to memory location: '(originated from NtWow64ReadVirtualMemory64)'

Test results

Traceback (most recent call last):
  File "<string>", line 1, in <module>
NameError: name 'psutil' is not defined

[dusans]

Works with 64 bit and psutil 5.7.2

I have tested the same thing with 64 bit and psutil 5.7.2 and there was no such issue.

I think this might be a bug in the Windows 32 bit layer.