René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Isolate the faulthandler Module Between Interpreters","articleBody":"(See gh-100227.)\r\n\r\nCurrently the faulthandler module has some state in `_PyRuntimeState`, including objects, which is shared by all interpreters.  Interpreters should be isolated from each other, for a variety of reasons (including the possibility of a per-interpreter GIL).  Isolating the module will involve moving some of the state to `PyInterpreterState` (and, under per-interpreter GIL, guarding other state with a global lock).\r\n\r\n----\r\n\r\nCode Analysis:\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003e(expand)\u003c/summary\u003e\r\n\r\n## Signals\r\n\r\nThe module installs handlers for various signals.\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003e(expand)\u003c/summary\u003e\r\n\r\n\u003cBR/\u003e\r\nfatal:\r\n\r\n* `SIGBUS` - bus error\r\n* `SIGILL` - illegal instruction\r\n* `SIGFPE` - floating point exception\r\n* `SIGABRT` - abort\r\n* `SIGSEGV` - segfault\r\n\r\n\"user\":\r\n\r\n* the 5 fatal signals\r\n* others (up to `Py_NSIG`)\r\n\r\nhandlers:\r\n\r\n* `faulthandler_fatal_error(signum)`\r\n* `faulthandler_exc_handler()`  (on Windows)\r\n* `faulthandler_user()`\r\n\r\n\u003c/details\u003e\r\n\r\n\r\n## State\r\n\r\n### Fields\r\n\r\nhttps://github.com/python/cpython/blob/main/Include/internal/pycore_faulthandler.h#L49-L86\r\nhttps://github.com/python/cpython/blob/main/Include/internal/pycore_runtime.h#L146\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003eraw\u003c/summary\u003e\r\n\r\nhttps://github.com/python/cpython/blob/62251c3da06eb4662502295697f39730565b1717/Include/internal/pycore_faulthandler.h#L49-L86\r\nhttps://github.com/python/cpython/blob/62251c3da06eb4662502295697f39730565b1717/Include/internal/pycore_faulthandler.h#L36-L46\r\n\u003c/details\u003e\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003etables:\u003c/summary\u003e\r\n\r\n\u003cBR/\u003e\r\n\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**type**\u003c/p\u003e | \u003cp align=\"center\"\u003e**\\#ifdef**\u003c/p\u003e | \u003cp align=\"center\"\u003e**notes**\u003c/p\u003e |\r\n| ---- | ---- | ---- | ---- |\r\n| `fatal_error` |  |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `enabled` | `bool` |  | \"is faulthandler enabled?\" |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | **`PyObject *`** |  | only for keeping `.fd` alive |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` | `int` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `all_threads` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | **`PyInterpreterState *`** |  | show only its threads\u003cBR/\u003ethe one that enabled faulthandler |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `exc_handler` | `void *` | `MS_WINDOWS` |  |\r\n|  |  |  |  |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**type**\u003c/p\u003e | \u003cp align=\"center\"\u003e**\\#ifdef**\u003c/p\u003e | \u003cp align=\"center\"\u003e**notes**\u003c/p\u003e |\r\n| `thread` | --- |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | *`PyObject *`* |  | only for keeping `.fd` alive |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` | `int` |  | defaults to `sys.stderr` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `timeout_us` | `PY_TIMEOUT_T` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `repeat` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | **`PyInterpreterState *`** |  | show only its threads\u003cBR/\u003ethe one that requested the info |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `exit` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `header` | `char *` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `header_len` | `size_t` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `cancel_event` | **`PyThread_type_lock`** |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `running` | **`PyThread_type_lock`** |  |  |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**type**\u003c/p\u003e | \u003cp align=\"center\"\u003e**\\#ifdef**\u003c/p\u003e | \u003cp align=\"center\"\u003e**notes**\u003c/p\u003e |\r\n| `user_signals` | **`struct faulthandler_user_signal *`** | `FAULTHANDLER_USER` | a dynamically allocated array (`Py_NSIG`) |\r\n| `user_signals[signum]` | --- |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `enabled` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | `PyObject *` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` | `int` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `all_threads` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `chain` | `bool` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `previous` | `_Py_sighandler_t` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | **`PyInterpreterState *`** |  | show only its threads\u003cBR/\u003ethe one that added the handler |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**type**\u003c/p\u003e | \u003cp align=\"center\"\u003e**\\#ifdef**\u003c/p\u003e | \u003cp align=\"center\"\u003e**notes**\u003c/p\u003e |\r\n| `old_stack` | `stack_t` | `FAULTHANDLER_USE_ALT_STACK` |  |\r\n| `stack` | `stack_t` | `FAULTHANDLER_USE_ALT_STACK` |  |\r\n\r\n\u003c/details\u003e\r\n\r\n\r\n### Usage\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003esimple:\u003c/summary\u003e\r\n\r\n\u003cBR/\u003e\r\n\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**context**\u003c/p\u003e | \u003cp align=\"center\"\u003e**get**\u003c/p\u003e | \u003cp align=\"center\"\u003e**set**\u003c/p\u003e |\r\n| ---- | ---- | ---- | ---- |\r\n| `fatal_error` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `enabled` | module | `faulthandler_is_enabled()` | `faulthandler_disable_py()` |\r\n|  | signal | `faulthandler_fatal_error()` |  |\r\n|  | internal | `faulthandler_enable()`\u003cBR/\u003e`faulthandler_disable()` | `faulthandler_enable()`\u003cBR/\u003e`faulthandler_disable()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | module | `faulthandler_traverse()` | `faulthandler_py_enable()`\u003cBR/\u003e`faulthandler_traverse()` |\r\n|  | internal | `faulthandler_disable()` | `faulthandler_disable()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` |  | module |  | `faulthandler_py_enable()` |\r\n|  | signal | `faulthandler_fatal_error()`\u003cBR/\u003e`faulthandler_exc_handler()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `all_threads` | module |  | `faulthandler_py_enable()` |\r\n|  | signal | `faulthandler_fatal_error()`\u003cBR/\u003e`faulthandler_exc_handler()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | module |  | `faulthandler_py_enable()` |\r\n|  | internal | `faulthandler_fatal_error()`\u003cBR/\u003e`faulthandler_exc_handler()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `exc_handler` | internal | `faulthandler_enable()`\u003cBR/\u003e`faulthandler_disable()` | `faulthandler_enable()`\u003cBR/\u003e`faulthandler_disable()` |\r\n|  |  |  |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**context**\u003c/p\u003e | \u003cp align=\"center\"\u003e**get**\u003c/p\u003e | \u003cp align=\"center\"\u003e**set**\u003c/p\u003e |\r\n| `thread` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | module | `faulthandler_dump_traceback_later()`\u003cBR/\u003e`faulthandler_traverse()` | `faulthandler_dump_traceback_later()`\u003cBR/\u003e`faulthandler_traverse()` |\r\n|  | internal | `cancel_dump_traceback_later()` | `cancel_dump_traceback_later()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` |\r\n module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `timeout_us` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `repeat` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `exit` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `header` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n|  | internal | `cancel_dump_traceback_later()` | `cancel_dump_traceback_later()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `header_len` | module |  | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `cancel_event` | module | `faulthandler_dump_traceback_later()` | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n|  | internal | `cancel_dump_traceback_later()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `running` | module | `faulthandler_dump_traceback_later()` | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |  |\r\n|  | internal | `cancel_dump_traceback_later()` |  |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**context**\u003c/p\u003e | \u003cp align=\"center\"\u003e**get**\u003c/p\u003e | \u003cp align=\"center\"\u003e**set**\u003c/p\u003e |\r\n| `user_signals` | module | `faulthandler_register_py()`\u003cBR/\u003e`faulthandler_unregister_py()` | `faulthandler_register_py()`\u003cBR/\u003e`faulthandler_traverse()` |\r\n|  | C-API | `_PyFaulthandler_Fini()` | `_PyFaulthandler_Fini()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n| `user_signals[signum]` |  |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `enabled` | module | `faulthandler_register_py()` | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n|  | internal | `faulthandler_unregister()` | `faulthandler_unregister()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `file` | module | `faulthandler_register_py()`\u003cBR/\u003e`faulthandler_traverse()` | `faulthandler_register_py()`\u003cBR/\u003e`faulthandler_traverse()` |\r\n|  | internal | `faulthandler_unregister()` | `faulthandler_unregister()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `fd` | module |  | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n|  | internal |  | `faulthandler_unregister()` |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `all_threads` | module |  | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `chain` | module |  | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `previous` | module |  | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n|  | internal | `faulthandler_unregister()` |  |\r\n| \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;. `interp` | module |  | `faulthandler_register_py()` |\r\n|  | signal | `faulthandler_user()` |  |\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**context**\u003c/p\u003e | \u003cp align=\"center\"\u003e**get**\u003c/p\u003e | \u003cp align=\"center\"\u003e**set**\u003c/p\u003e |\r\n| `stack` | C-API | `_PyFaulthandler_Init()`\u003cBR/\u003e`_PyFaulthandler_Fini()` |  |\r\n|  | internal | `faulthandler_enable()`\u003cBR/\u003e`faulthandler_register()`\u003cBR/\u003e`faulthandler_allocate_stack()` |  |\r\n| `old_stack` | C-API | `_PyFaulthandler_Fini()` |  |\r\n\r\n\u003c/details\u003e\r\n\r\n\u003cdetails\u003e\r\n\u003csummary\u003emodify data in complex fields:\u003c/summary\u003e\r\n\r\n\u003cBR/\u003e\r\n\r\n| \u003cp align=\"center\"\u003e**name**\u003c/p\u003e | \u003cp align=\"center\"\u003e**context**\u003c/p\u003e | \u003cp align=\"center\"\u003e**calls**\u003c/p\u003e |\r\n| ---- | ---- | ---- |\r\n| `fatal_error .fd` | signal | `faulthandler_fatal_error()` -\u003e `faulthandler_dump_traceback()`\u003cBR/\u003e`faulthandler_fatal_error()` -\u003e `_Py_DumpExtensionModules()`\u003cBR/\u003e`faulthandler_exc_handler()`\u003cBR/\u003e`faulthandler_exc_handler()` -\u003e `_Py_DumpHexadecimal()`\u003cBR/\u003e`faulthandler_exc_handler()` -\u003e `faulthandler_dump_traceback()` |\r\n| `thread.fd` | thread | `faulthandler_thread()` -\u003e `_Py_write_noraise()`\u003cBR/\u003e`faulthandler_thread()` -\u003e `_Py_DumpTracebackThreads()` |\r\n| `thread .cancel_event` | module | `faulthandler_dump_traceback_later()` |\r\n|  | C-API | `_PyFaulthandler_Fini()` |\r\n|  | thread | `faulthandler_thread()` |\r\n|  | internal | `cancel_dump_traceback_later()` |\r\n| `thread .running` | module | `faulthandler_dump_traceback_later()` |\r\n|  | thread | `faulthandler_thread()` |\r\n|  | internal | `cancel_dump_traceback_later()` |\r\n| `user_signals[signum] .fd` | signal | `faulthandler_user()` -\u003e `faulthandler_dump_traceback()` |\r\n| `stack` | C-API | `_PyFaulthandler_Init()`\u003cBR/\u003e`_PyFaulthandler_Fini()` |\r\n|  | internal | `faulthandler_allocate_stack()` |\r\n| `old_stack` | internal | `faulthandler_allocate_stack()` -\u003e `sigaltstack()` |\r\n\r\n\u003c/details\u003e\r\n\r\n\u003c/details\u003e","author":{"url":"https://github.com/ericsnowcurrently","@type":"Person","name":"ericsnowcurrently"},"datePublished":"2023-02-01T22:37:12.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/101509/cpython/issues/101509"}