Uncaught exceptions when using Unicorn concurrently

[jhhcs]

Hey! I am maintaining a downstream project that was using

2.0.1.post1

until recently. I have now upgraded to the most recent release:

2.1.4

This has gone through without problems for my test suites on but the Windows runners also report a barrage of exceptions. I can reproduce these locally and have isolated the error output below.

Very notably, I use pytest-xdist to execute these tests in parallel. These errors do not occur when the test suite is executed in a single thread. It can be reproduced with the following code:

import unittest

import unicorn as uc
import unicorn.x86_const as x86

from unicorn.unicorn import Uc


def hook_mem_error(emu: Uc, access: int, address: int, size: int, value: int):
    aligned = address & ~0xFFF
    alloc_size = 0
    while address + size >= aligned + alloc_size:
        alloc_size += 0x1000
    emu.mem_map(aligned, alloc_size)
    return True


def hook_mem_read(emu: Uc, access: int, address: int, size: int, value: int) -> bool:
    print(F'{address:#016x} >> {value:#0{2 * size}x}')
    return True


def hook_mem_write(emu: Uc, access: int, address: int, size: int, value: int) -> bool:
    print(F'{address:#016x} << {value:#0{2 * size}x}')
    return True


CODE = bytes.fromhex(
    'B8 02 00 00 00'        # mov     eax, 2
    '66 89 05 19 DC 01 00'  # mov     [eip+0x1DC19], ax
    '66 B9 92 13'           # mov     cx, 0x1392
    'FF 15 AF 11 01 00'     # call    htons
    '66 89 05 0A DC 01 00'  # mov     [eip+0x1DC0A], ax
)


class Test(unittest.TestCase):

    def _emulator_test(self):
        mu = Uc(uc.UC_ARCH_X86, uc.UC_MODE_64)
        mu.mem_map(0, 0x1000)
        mu.mem_write(0, CODE)

        stack_len = 0x3000
        stack_top = 0x7fffffffffffc000
        stack_ptr = 0x7fffffffffffe000

        ip = 0

        mu.mem_map(stack_top, stack_len)
        mu.reg_write(x86.UC_X86_REG_RSP, stack_ptr)
        mu.reg_write(x86.UC_X86_REG_RIP, ip)

        mu.hook_add(uc.UC_HOOK_MEM_READ, hook_mem_read)
        mu.hook_add(uc.UC_HOOK_MEM_WRITE, hook_mem_write)
        mu.hook_add(uc.UC_HOOK_MEM_INVALID, hook_mem_error)

        mu.emu_start(ip, 5)
        ip = mu.reg_read(x86.UC_X86_REG_RIP)

        self.assertEqual(ip, 5)

    def test_uc1(self): self._emulator_test()
    def test_uc2(self): self._emulator_test()
    def test_uc3(self): self._emulator_test()
    def test_uc4(self): self._emulator_test()
    def test_uc5(self): self._emulator_test()
    def test_uc6(self): self._emulator_test()
    def test_uc7(self): self._emulator_test()
    def test_uc8(self): self._emulator_test()

Running

pytest -n 4 test 2>test.errors

produces the following output for me:

Windows fatal exception: access violation

Thread 0x00003338 (most recent call first):
  File "C:\Workspace\projects\refinery-mvp\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File Windows fatal exception: access violation

Thread 0x00002f28 (most recent call first):
"X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x000041b4 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 69 in test_uc7
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py"Windows fatal exception:   File Windows fatal exception: access violation

"X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x00000514 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 63 in test_uc1
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>
Thread 0x000024d4 (most recent call first):
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341, line  in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411121 in _perform_spawn

Current thread 0x00000740 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 67 in test_uc5
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File  in "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File Windows fatal exception: access violation

Thread 0x00003338 (most recent call first):
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
access violation

  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver_multicall"X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>
Thread 0x0000317c (most recent call first):


  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x000041b4 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 70 in test_uc8
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x00005634 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 65 in test_uc3
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File Windows fatal exception: access violation

Thread 0x000024d4 (most recent call first):
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x00000740 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 68 in test_uc6
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
"  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py" in X:\test\venv\Lib\site-packages\xdist\remote.py  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "runtest", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>

  File , line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py"X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>
X:\test\venv\Lib\site-packages\_pytest\runner.py"", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File , line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py""X:\test\venv\Lib\site-packages\xdist\remote.py", line 427 in <module>
, line   File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>
121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicallWindows fatal exception: access violation

Thread 0x0000317c (most recent call first):
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
Windows fatal exception:   File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x00005634 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 66 in test_uc4
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in 
__call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py"access violation, line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>


Thread 0x00002f28 (most recent call first):
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 534 in read
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 567 in from_io
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1160 in _thread_receiver
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn

Current thread 0x00000514 (most recent call first):
  File "X:\test\venv\Lib\site-packages\unicorn\unicorn_py3\unicorn.py", line 831 in mem_map
  File "X:\test\test\test_unicorn.py", line 41 in _emulator_test
  File "X:\test\test\test_unicorn.py", line 64 in test_uc2
  File "C:\Python314\Lib\unittest\case.py", line 615 in _callTestMethod
  File "C:\Python314\Lib\unittest\case.py", line 669 in run
  File "C:\Python314\Lib\unittest\case.py", line 725 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\unittest.py", line 389 in runtest
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 179 in pytest_runtest_call
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 245 in <lambda>
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 353 in from_call
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 244 in call_and_report
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 137 in runtestprotocol
  File "X:\test\venv\Lib\site-packages\_pytest\runner.py", line 118 in pytest_runtest_protocol
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 227 in run_one_test
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 206 in pytest_runtestloop
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 372 in _main
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 318 in wrap_session
  File "X:\test\venv\Lib\site-packages\_pytest\main.py", line 365 in pytest_cmdline_main
  File "X:\test\venv\Lib\site-packages\pluggy\_callers.py", line 121 in _multicall
  File "X:\test\venv\Lib\site-packages\pluggy\_manager.py", line 120 in _hookexec
  File "X:\test\venv\Lib\site-packages\pluggy\_hooks.py", line 512 in __call__
  File "X:\test\venv\Lib\site-packages\xdist\remote.py", line 427 in <module>
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1291 in executetask
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 341 in run
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 411 in _perform_spawn
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 389 in integrate_as_primary_thread
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1273 in serve
  File "X:\test\venv\Lib\site-packages\execnet\gateway_base.py", line 1806 in serve
  File "<string>", line 8 in <module>
  File "<string>", line 1 in <module>

Current thread's C stack trace (most recent call first):
  <cannot get C stack on this system>

[wtdcode]

Is it possible that it simply runs out of memory? We (Qiling) once had exactly the same issue and we resolved it with https://github.com/al-cheb/configure-pagefile-action

[jhhcs]

That's a good idea, thank you, but that's not it. My local setup has 64GB and I checked: The MVP I posted above doesn't even scratch the surface of that (neither does my actual test suite for that matter).

[Ottavio97]

I can confirm there's a issue using emulator concurrently, even with different instances. I'm on C++ and with 2 threads running in tight fast loops, there are randomic ACCESS_VIOLATION exceptions. If I throttle the loop a little bit, exceptions disappear. This could mean that there's a race condition over shared memory between uc instances. Tested with both 2.1.4 and "master" branch

[jhhcs]

I think I have identified the issue: On Windows, unicorn allocates its code generation buffer with

VirtualAlloc(..., MEM_RESERVE, ...) 

reserving address space without committing physical pages. It then registers a VEH that catches the resulting access violations on first touch and commits pages on demand via MEM_COMMIT. Python's faulthandler module (enabled by default in pytest and other tools) registers its own VEH at higher priority! It catches each access violation before unicorn can handle them, thus we get

Windows fatal exception: access violation

for every time an uncommitted page is touched. One option would be to simply register at the front of the chain:

-    uc->seh_handle = AddVectoredExceptionHandler(0, (PVECTORED_EXCEPTION_HANDLER)closure);
+    uc->seh_handle = AddVectoredExceptionHandler(1, (PVECTORED_EXCEPTION_HANDLER)closure);

This would literally be a one-character fix for the issue and I am filing a meme PR with this momentarily.

[jhhcs]

PS: To elaborate, the concurrency was a red herring. The issue can also be reproduced with a single instance. This is enough:

import faulthandler
faulthandler.enable()
from unicorn import *
mu = Uc(UC_ARCH_X86, UC_MODE_64)
mu.mem_map(0x1000000, 0x1000)