cpython/Modules/_remote_debugging/module.c at main · python/cpython · GitHub

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/******************************************************************************

* Remote Debugging Module - Main Module Implementation

* This file contains the main module initialization, the RemoteUnwinder

* class implementation, and utility functions.

******************************************************************************/

#include "_remote_debugging.h"

#include "binary_io.h"

#include "debug_offsets_validation.h"

#include "gc_stats.h"

/* Forward declarations for clinic-generated code */

typedef struct {

PyObject_HEAD

BinaryWriter *writer;

uint64_t cached_total_samples; /* Preserved after finalize */

} BinaryWriterObject;

typedef struct {

PyObject_HEAD

BinaryReader *reader;

} BinaryReaderObject;

#include "clinic/module.c.h"

/* ============================================================================

* STRUCTSEQ TYPE DEFINITIONS

* ============================================================================ */

// TaskInfo structseq type

static PyStructSequence_Field TaskInfo_fields[] = {

{"task_id", "Task ID (memory address)"},

{"task_name", "Task name"},

{"coroutine_stack", "Coroutine call stack"},

{"awaited_by", "Tasks awaiting this task"},

{NULL}

};

PyStructSequence_Desc TaskInfo_desc = {

"_remote_debugging.TaskInfo",

"Information about an asyncio task",

TaskInfo_fields,

};

// LocationInfo structseq type

static PyStructSequence_Field LocationInfo_fields[] = {

{"lineno", "Line number"},

{"end_lineno", "End line number"},

{"col_offset", "Column offset"},

{"end_col_offset", "End column offset"},

{NULL}

};

PyStructSequence_Desc LocationInfo_desc = {

"_remote_debugging.LocationInfo",

"Source location information: (lineno, end_lineno, col_offset, end_col_offset)",

LocationInfo_fields,

};

// FrameInfo structseq type

static PyStructSequence_Field FrameInfo_fields[] = {

{"filename", "Source code filename"},

{"location", "LocationInfo structseq or None for synthetic frames"},

{"funcname", "Function name"},

{"opcode", "Opcode being executed (None if not gathered)"},

{NULL}

};

PyStructSequence_Desc FrameInfo_desc = {

"_remote_debugging.FrameInfo",

"Information about a frame",

FrameInfo_fields,

};

// CoroInfo structseq type

static PyStructSequence_Field CoroInfo_fields[] = {

{"call_stack", "Coroutine call stack"},

{"task_name", "Task name"},

{NULL}

};

PyStructSequence_Desc CoroInfo_desc = {

"_remote_debugging.CoroInfo",

"Information about a coroutine",

CoroInfo_fields,

};

// ThreadInfo structseq type

static PyStructSequence_Field ThreadInfo_fields[] = {

{"thread_id", "Thread ID"},

{"status", "Thread status (flags: HAS_GIL, ON_CPU, UNKNOWN or legacy enum)"},

{"frame_info", "Frame information"},

{NULL}

};

PyStructSequence_Desc ThreadInfo_desc = {

"_remote_debugging.ThreadInfo",

"Information about a thread",

ThreadInfo_fields,

};

// InterpreterInfo structseq type

static PyStructSequence_Field InterpreterInfo_fields[] = {

{"interpreter_id", "Interpreter ID"},

{"threads", "List of threads in this interpreter"},

{NULL}

};

PyStructSequence_Desc InterpreterInfo_desc = {

"_remote_debugging.InterpreterInfo",

"Information about an interpreter",

InterpreterInfo_fields,

};

// AwaitedInfo structseq type

static PyStructSequence_Field AwaitedInfo_fields[] = {

{"thread_id", "Thread ID"},

{"awaited_by", "List of tasks awaited by this thread"},

{NULL}

};

PyStructSequence_Desc AwaitedInfo_desc = {

"_remote_debugging.AwaitedInfo",

"Information about what a thread is awaiting",

AwaitedInfo_fields,

};

// GCStatsInfo structseq type

static PyStructSequence_Field GCStatsInfo_fields[] = {

{"gen", "GC generation number"},

{"iid", "Interpreter ID"},

{"ts_start", "Raw timestamp at collection start"},

{"ts_stop", "Raw timestamp at collection stop"},

{"collections", "Total number of collections"},

{"collected", "Total number of collected objects"},

{"uncollectable", "Total number of uncollectable objects"},

{"candidates", "Total objects considered and traversed"},

{"heap_size", "Number of live objects"},

{"duration", "Total collection time, in seconds"},

{NULL}

};

PyStructSequence_Desc GCStatsInfo_desc = {

"_remote_debugging.GCStatsInfo",

"Information about a garbage collector stats sample",

GCStatsInfo_fields,

};

/* ============================================================================

* UTILITY FUNCTIONS

* ============================================================================ */

void

cached_code_metadata_destroy(void *ptr)

{

CachedCodeMetadata *meta = (CachedCodeMetadata *)ptr;

Py_DECREF(meta->func_name);

Py_DECREF(meta->file_name);

Py_DECREF(meta->linetable);

Py_XDECREF(meta->last_frame_info);

PyMem_RawFree(meta);

}

RemoteDebuggingState *

RemoteDebugging_GetState(PyObject *module)

{

void *state = _PyModule_GetState(module);

assert(state != NULL);

return (RemoteDebuggingState *)state;

}

RemoteDebuggingState *

RemoteDebugging_GetStateFromType(PyTypeObject *type)

{

PyObject *module = PyType_GetModule(type);

assert(module != NULL);

return RemoteDebugging_GetState(module);

}

RemoteDebuggingState *

RemoteDebugging_GetStateFromObject(PyObject *obj)

{

RemoteUnwinderObject *unwinder = (RemoteUnwinderObject *)obj;

if (unwinder->cached_state == NULL) {

unwinder->cached_state = RemoteDebugging_GetStateFromType(Py_TYPE(obj));

}

return unwinder->cached_state;

}

int

RemoteDebugging_InitState(RemoteDebuggingState *st)

{

return 0;

}

int

is_prerelease_version(uint64_t version)

{

return (version & 0xF0) != 0xF0;

}

int

validate_debug_offsets(struct _Py_DebugOffsets *debug_offsets)

{

if (memcmp(debug_offsets->cookie, _Py_Debug_Cookie, sizeof(debug_offsets->cookie)) != 0) {

// The remote is probably running a Python version predating debug offsets.

PyErr_SetString(

PyExc_RuntimeError,

"Can't determine the Python version of the remote process");

return -1;

}

// Assume debug offsets could change from one pre-release version to another,

// or one minor version to another, but are stable across patch versions.

if (is_prerelease_version(Py_Version) && Py_Version != debug_offsets->version) {

PyErr_SetString(

PyExc_RuntimeError,

"Can't attach from a pre-release Python interpreter"

" to a process running a different Python version");

return -1;

}

if (is_prerelease_version(debug_offsets->version) && Py_Version != debug_offsets->version) {

PyErr_SetString(

PyExc_RuntimeError,

"Can't attach to a pre-release Python interpreter"

" from a process running a different Python version");

return -1;

}

unsigned int remote_major = (debug_offsets->version >> 24) & 0xFF;

unsigned int remote_minor = (debug_offsets->version >> 16) & 0xFF;

if (PY_MAJOR_VERSION != remote_major || PY_MINOR_VERSION != remote_minor) {

PyErr_Format(

PyExc_RuntimeError,

"Can't attach from a Python %d.%d process to a Python %d.%d process",

PY_MAJOR_VERSION, PY_MINOR_VERSION, remote_major, remote_minor);

return -1;

}

// The debug offsets differ between free threaded and non-free threaded builds.

if (_Py_Debug_Free_Threaded && !debug_offsets->free_threaded) {

PyErr_SetString(

PyExc_RuntimeError,

"Cannot attach from a free-threaded Python process"

" to a process running a non-free-threaded version");

return -1;

}

if (!_Py_Debug_Free_Threaded && debug_offsets->free_threaded) {

PyErr_SetString(

PyExc_RuntimeError,

"Cannot attach to a free-threaded Python process"

" from a process running a non-free-threaded version");

return -1;

}

return _PyRemoteDebug_ValidateDebugOffsetsLayout(debug_offsets);

}

/* ============================================================================

* REMOTEUNWINDER CLASS IMPLEMENTATION

* ============================================================================ */

/*[clinic input]

module _remote_debugging

class _remote_debugging.RemoteUnwinder "RemoteUnwinderObject *" "&RemoteUnwinder_Type"

[clinic start generated code]*/

/*[clinic end generated code: output=da39a3ee5e6b4b0d input=12b4dce200381115]*/

/*[clinic input]

@permit_long_summary

_remote_debugging.RemoteUnwinder.__init__

pid: pid_t

all_threads: bool = False

only_active_thread: bool = False

mode: int = 0

debug: bool = False

skip_non_matching_threads: bool = True

native: bool = False

gc: bool = False

opcodes: bool = False

cache_frames: bool = False

stats: bool = False

Initialize a new RemoteUnwinder object for debugging a remote Python process.

Args:

pid: Process ID of the target Python process to debug

all_threads: If True, initialize state for all threads in the

process. If False, only initialize for the main thread.

only_active_thread: If True, only sample the thread holding the GIL.

mode: Profiling mode: 0=WALL (wall-time), 1=CPU (cpu-time), 2=GIL

(gil-time). Cannot be used together with all_threads=True.

debug: If True, chain exceptions to explain the sequence of events

that lead to the exception.

skip_non_matching_threads: If True, skip threads that don't match

the selected mode. If False, include all threads regardless of

mode.

native: If True, include artificial "<native>" frames to denote

calls to non-Python code.

gc: If True, include artificial "<GC>" frames to denote active

garbage collection.

opcodes: If True, gather bytecode opcode information for

instruction-level profiling.

cache_frames: If True, enable frame caching optimization to avoid

re-reading unchanged parent frames between samples.

stats: If True, collect statistics about cache hits, memory reads,

etc. Use get_stats() to retrieve the collected statistics.

The RemoteUnwinder provides functionality to inspect and debug a running

Python process, including examining thread states, stack frames and

other runtime data.

Raises:

PermissionError: If access to the target process is denied

OSError: If unable to attach to the target process or access its

memory

RuntimeError: If unable to read debug information from the target

process

ValueError: If both all_threads and only_active_thread are True

[clinic start generated code]*/

static int

_remote_debugging_RemoteUnwinder___init___impl(RemoteUnwinderObject *self,

pid_t pid, int all_threads,

int only_active_thread,

int mode, int debug,

int skip_non_matching_threads,

int native, int gc,

int opcodes, int cache_frames,

int stats)

/*[clinic end generated code: output=acfe554c8a92cf6b input=3b5a5ad153709125]*/

{

// Validate that all_threads and only_active_thread are not both True

if (all_threads && only_active_thread) {

PyErr_SetString(PyExc_ValueError,

"all_threads and only_active_thread cannot both be True");

return -1;

}

#ifdef Py_GIL_DISABLED

if (only_active_thread) {

PyErr_SetString(PyExc_ValueError,

"only_active_thread is not supported in free-threaded builds");

return -1;

}

#endif

self->native = native;

self->gc = gc;

self->opcodes = opcodes;

self->cache_frames = cache_frames;

self->collect_stats = stats;

self->stale_invalidation_counter = 0;

self->cached_tstate_interpreter_addr = 0;

self->cached_tstate_addr = 0;

memset(self->cached_tstates, 0, sizeof(self->cached_tstates));

memset(self->cached_generations, 0, sizeof(self->cached_generations));

self->debug = debug;

self->only_active_thread = only_active_thread;

self->mode = mode;

self->skip_non_matching_threads = skip_non_matching_threads;

self->cached_state = NULL;

self->frame_cache = NULL;

#ifdef Py_REMOTE_DEBUG_SUPPORTS_BLOCKING

self->threads_stopped = 0;

#endif

// Initialize stats to zero

memset(&self->stats, 0, sizeof(self->stats));

if (_Py_RemoteDebug_InitProcHandle(&self->handle, pid) < 0) {

set_exception_cause(self, PyExc_RuntimeError, "Failed to initialize process handle");

return -1;

}

self->runtime_start_address = _Py_RemoteDebug_GetPyRuntimeAddress(&self->handle);

if (self->runtime_start_address == 0) {

set_exception_cause(self, PyExc_RuntimeError, "Failed to get Python runtime address");

return -1;

}

if (_Py_RemoteDebug_ReadDebugOffsets(&self->handle,

&self->runtime_start_address,

&self->debug_offsets) < 0)

{

set_exception_cause(self, PyExc_RuntimeError, "Failed to read debug offsets");

return -1;

}

// Validate that the debug offsets are valid

if (validate_debug_offsets(&self->debug_offsets) == -1) {

set_exception_cause(self, PyExc_RuntimeError, "Invalid debug offsets found");

return -1;

}

// Try to read async debug offsets, but don't fail if they're not available

self->async_debug_offsets_available = 1;

int async_debug_result = read_async_debug(self);

if (async_debug_result == PY_REMOTE_DEBUG_INVALID_ASYNC_DEBUG_OFFSETS) {

return -1;

}

if (async_debug_result < 0) {

if (_Py_RemoteDebug_HasPermissionError()) {

return -1;

}

PyErr_Clear();

memset(&self->async_debug_offsets, 0, sizeof(self->async_debug_offsets));

self->async_debug_offsets_available = 0;

}

if (populate_initial_state_data(all_threads, self, self->runtime_start_address,

&self->interpreter_addr ,&self->tstate_addr) < 0)

{

set_exception_cause(self, PyExc_RuntimeError, "Failed to populate initial state data");

return -1;

}

self->code_object_cache = _Py_hashtable_new_full(

_Py_hashtable_hash_ptr,

_Py_hashtable_compare_direct,

NULL, // keys are stable pointers, don't destroy

cached_code_metadata_destroy,

NULL

);

if (self->code_object_cache == NULL) {

PyErr_NoMemory();

set_exception_cause(self, PyExc_MemoryError, "Failed to create code object cache");

return -1;

}

#ifdef Py_GIL_DISABLED

// Initialize TLBC cache

self->tlbc_generation = 0;

self->tlbc_cache = _Py_hashtable_new_full(

_Py_hashtable_hash_ptr,

_Py_hashtable_compare_direct,

NULL, // keys are stable pointers, don't destroy

tlbc_cache_entry_destroy,

NULL

);

if (self->tlbc_cache == NULL) {

_Py_hashtable_destroy(self->code_object_cache);

PyErr_NoMemory();

set_exception_cause(self, PyExc_MemoryError, "Failed to create TLBC cache");

return -1;

}

#endif

#if defined(__APPLE__)

self->thread_id_offset = 0;

self->thread_id_offset_initialized = 0;

#endif

#ifdef MS_WINDOWS

self->win_process_buffer = NULL;

self->win_process_buffer_size = 0;

#endif

#ifdef __linux__

self->thread_tids = NULL;

self->thread_tids_capacity = 0;

#endif

if (cache_frames && frame_cache_init(self) < 0) {

return -1;

}

// Clear stale profiler anchors from previous profilers. This prevents us

// from stopping frame walking early due to stale frame pointers.

if (cache_frames) {

clear_last_profiled_frames(self);

}

return 0;

}

static inline size_t

interpreter_thread_cache_index(uintptr_t interpreter_addr)

{

// Direct-mapped table indexed by the remote interpreter address. Each entry

// stores the full address and verifies it on lookup, so hash collisions

// degrade to misses and cannot return a value from the wrong interpreter.

return (size_t)_Py_HashPointerRaw((const void *)interpreter_addr)

& (INTERPRETER_THREAD_CACHE_SIZE - 1);

}

static inline uintptr_t

get_cached_tstate_for_interpreter(

RemoteUnwinderObject *self,

uintptr_t interpreter_addr)

{

if (interpreter_addr == 0) {

return 0;

}

if (self->cached_tstate_interpreter_addr == interpreter_addr) {

return self->cached_tstate_addr;

}

InterpreterTstateCacheEntry *entry =

&self->cached_tstates[interpreter_thread_cache_index(interpreter_addr)];

if (entry->interpreter_addr == interpreter_addr) {

self->cached_tstate_interpreter_addr = interpreter_addr;

self->cached_tstate_addr = entry->thread_state_addr;

return entry->thread_state_addr;

}

return 0;

}

static inline void

set_cached_tstate_for_interpreter(

RemoteUnwinderObject *self,

uintptr_t interpreter_addr,

uintptr_t thread_state_addr)

{

if (interpreter_addr == 0 || thread_state_addr == 0) {

return;

}

self->cached_tstate_interpreter_addr = interpreter_addr;

self->cached_tstate_addr = thread_state_addr;

InterpreterTstateCacheEntry *entry =

&self->cached_tstates[interpreter_thread_cache_index(interpreter_addr)];

entry->interpreter_addr = interpreter_addr;

entry->thread_state_addr = thread_state_addr;

}

static void

refresh_generation_caches_from_interp_state(

RemoteUnwinderObject *self,

uintptr_t interpreter_addr,

const char *interp_state_buffer)

{

uint64_t code_object_generation = GET_MEMBER(uint64_t, interp_state_buffer,

self->debug_offsets.interpreter_state.code_object_generation);

if (self->cached_generation_interpreter_addr == interpreter_addr) {

if (code_object_generation != self->cached_code_object_generation) {

self->cached_code_object_generation = code_object_generation;

_Py_hashtable_clear(self->code_object_cache);

}

else {

InterpreterGenerationCacheEntry *entry =

&self->cached_generations[interpreter_thread_cache_index(interpreter_addr)];

// A slot rebound from another interpreter must be treated as changed:

// the code_object_cache is global, so even if the new generation

// numerically matches what the previous occupant had, stale entries

// from that occupant could still be served.

int changed = entry->interpreter_addr != interpreter_addr

|| entry->code_object_generation != code_object_generation;

entry->interpreter_addr = interpreter_addr;

entry->code_object_generation = code_object_generation;

if (changed) {

_Py_hashtable_clear(self->code_object_cache);

}

self->cached_generation_interpreter_addr = interpreter_addr;

self->cached_code_object_generation = code_object_generation;

}

#ifdef Py_GIL_DISABLED

uint32_t current_tlbc_generation = GET_MEMBER(uint32_t, interp_state_buffer,

self->debug_offsets.interpreter_state.tlbc_generation);

if (current_tlbc_generation != self->tlbc_generation) {

self->tlbc_generation = current_tlbc_generation;

_Py_hashtable_clear(self->tlbc_cache);

}

#endif

}

static int

refresh_generation_caches_for_interpreter(

RemoteUnwinderObject *self,

uintptr_t interpreter_addr)

{

char interp_state_buffer[INTERP_STATE_BUFFER_SIZE];

if (_Py_RemoteDebug_ReadRemoteMemory(

&self->handle,

interpreter_addr,

INTERP_STATE_BUFFER_SIZE,

interp_state_buffer) < 0) {

set_exception_cause(self, PyExc_RuntimeError,

"Failed to read interpreter state buffer");

return -1;

}

refresh_generation_caches_from_interp_state(self, interpreter_addr, interp_state_buffer);

return 0;

}

static int

read_interp_state_and_maybe_thread_frame(

RemoteUnwinderObject *unwinder,

uintptr_t interpreter_addr,

char *interp_state_buffer,

char *tstate_buffer,

char *frame_buffer,

RemoteReadPrefetch *prefetch)

{

prefetch->tstate = NULL;

prefetch->frame = NULL;

if (prefetch->tstate_addr != 0) {

size_t tstate_size = (size_t)unwinder->debug_offsets.thread_state.size;

_Py_RemoteReadSegment segments[3] = {

{interpreter_addr, interp_state_buffer, INTERP_STATE_BUFFER_SIZE},

{prefetch->tstate_addr, tstate_buffer, tstate_size},

{prefetch->frame_addr, frame_buffer, SIZEOF_INTERP_FRAME},

};

int nsegs = prefetch->frame_addr != 0 ? 3 : 2;

Py_ssize_t nread = _Py_RemoteDebug_BatchedReadRemoteMemory(

&unwinder->handle, segments, nsegs);

int completed = 0;

if (nread >= (Py_ssize_t)INTERP_STATE_BUFFER_SIZE) {

completed = 1;

Py_ssize_t with_tstate = (Py_ssize_t)INTERP_STATE_BUFFER_SIZE

+ (Py_ssize_t)tstate_size;

if (nread >= with_tstate) {

completed = 2;

}

if (nsegs == 3

&& nread == with_tstate + (Py_ssize_t)SIZEOF_INTERP_FRAME) {

completed = 3;

}

STATS_BATCHED_READ(unwinder, nsegs, completed);

if (completed >= 1) {

if (completed >= 2) {

prefetch->tstate = tstate_buffer;

}

if (completed >= 3) {

prefetch->frame = frame_buffer;

}

return 0;

}

return _Py_RemoteDebug_ReadRemoteMemory(

&unwinder->handle,

interpreter_addr,

INTERP_STATE_BUFFER_SIZE,

interp_state_buffer);

}

/*[clinic input]

@critical_section

_remote_debugging.RemoteUnwinder.get_stack_trace

Returns stack traces for all interpreters and threads in process.

Each element in the returned list is a tuple of (interpreter_id,

thread_list), where:

- interpreter_id is the interpreter identifier

- thread_list is a list of tuples (thread_id, frame_list) for

threads in that interpreter

- thread_id is the OS thread identifier

- frame_list is a list of tuples (function_name, filename,

line_number) representing the Python stack frames for that

thread, ordered from most recent to oldest

The threads returned depend on the initialization parameters:

- If only_active_thread was True: returns only the thread holding

the GIL across all interpreters

- If all_threads was True: returns all threads across all

interpreters

- Otherwise: returns only the main thread of each interpreter

Example:

[

(0, [ # Main interpreter

(1234, [

('process_data', 'worker.py', 127),

('run_worker', 'worker.py', 45),

('main', 'app.py', 23)

]),

(1235, [

('handle_request', 'server.py', 89),

('serve_forever', 'server.py', 52)

])

]),

(1, [ # Sub-interpreter

(1236, [

('sub_worker', 'sub.py', 15)

])

]

Raises:

RuntimeError: If there is an error copying memory from the

target process

OSError: If there is an error accessing the target process

PermissionError: If access to the target process is denied

UnicodeDecodeError: If there is an error decoding strings from

the target process

[clinic start generated code]*/

static PyObject *

_remote_debugging_RemoteUnwinder_get_stack_trace_impl(RemoteUnwinderObject *self)

/*[clinic end generated code: output=666192b90c69d567 input=86a992b853f48aa9]*/

{

STATS_INC(self, total_samples);

PyObject* result = PyList_New(0);

if (!result) {

set_exception_cause(self, PyExc_MemoryError, "Failed to create stack trace result list");

return NULL;

}

// Iterate over all interpreters

uintptr_t current_interpreter = self->interpreter_addr;

while (current_interpreter != 0) {

// Read interpreter state to get the interpreter ID

char interp_state_buffer[INTERP_STATE_BUFFER_SIZE];

char prefetched_tstate[SIZEOF_THREAD_STATE];

char prefetched_frame[SIZEOF_INTERP_FRAME];

RemoteReadPrefetch prefetch = {0};

if (self->cache_frames) {

prefetch.tstate_addr = get_cached_tstate_for_interpreter(

self, current_interpreter);

}

if (prefetch.tstate_addr != 0) {

FrameCacheEntry *entry = frame_cache_find_by_tstate(self, prefetch.tstate_addr);

if (entry && entry->num_addrs > 0) {

prefetch.frame_addr = entry->addrs[0];

}

if (read_interp_state_and_maybe_thread_frame(

self,

current_interpreter,

interp_state_buffer,

prefetched_tstate,

prefetched_frame,

&prefetch) < 0) {

set_exception_cause(self, PyExc_RuntimeError, "Failed to read interpreter state buffer");

Py_CLEAR(result);

goto exit;

}

refresh_generation_caches_from_interp_state(self, current_interpreter, interp_state_buffer);

uintptr_t gc_frame = 0;

if (self->gc) {

gc_frame = GET_MEMBER(uintptr_t, interp_state_buffer,

self->debug_offsets.interpreter_state.gc

+ self->debug_offsets.gc.frame);

}

int64_t interpreter_id = GET_MEMBER(int64_t, interp_state_buffer,

self->debug_offsets.interpreter_state.id);

// Create a list to hold threads for this interpreter

PyObject *interpreter_threads = PyList_New(0);

if (!interpreter_threads) {

set_exception_cause(self, PyExc_MemoryError, "Failed to create interpreter threads list");

Py_CLEAR(result);

goto exit;

}

// Get the GIL holder for this interpreter (needed for GIL_WAIT logic)

uintptr_t gil_holder_tstate = 0;

int gil_locked = GET_MEMBER(int, interp_state_buffer,

self->debug_offsets.interpreter_state.gil_runtime_state_locked);

if (gil_locked) {

gil_holder_tstate = (uintptr_t)GET_MEMBER(PyThreadState*, interp_state_buffer,

self->debug_offsets.interpreter_state.gil_runtime_state_holder);

}

uintptr_t current_tstate;

if (self->only_active_thread) {

// Find the GIL holder for THIS interpreter

if (!gil_locked) {

// This interpreter's GIL is not locked, skip it

Py_DECREF(interpreter_threads);

goto next_interpreter;

}

current_tstate = gil_holder_tstate;

} else if (self->tstate_addr == 0) {

// Get all threads for this interpreter

current_tstate = GET_MEMBER(uintptr_t, interp_state_buffer,

self->debug_offsets.interpreter_state.threads_head);

} else {

// Target specific thread (only process first interpreter)

current_tstate = self->tstate_addr;

}

if (current_tstate != 0 && self->cache_frames) {

set_cached_tstate_for_interpreter(self, current_interpreter, current_tstate);

}

// Acquire main thread state information

uintptr_t main_thread_tstate = GET_MEMBER(uintptr_t, interp_state_buffer,

self->debug_offsets.interpreter_state.threads_main);

while (current_tstate != 0) {

uintptr_t prev_tstate = current_tstate;

PyObject* frame_info = unwind_stack_for_thread(self, &current_tstate,

gil_holder_tstate,

gc_frame,

main_thread_tstate,

&prefetch);

if (!frame_info) {

// Check if this was an intentional skip due to mode-based filtering

if ((self->mode == PROFILING_MODE_CPU || self->mode == PROFILING_MODE_GIL ||

self->mode == PROFILING_MODE_EXCEPTION) && !PyErr_Occurred()) {

// Detect cycle: if current_tstate didn't advance, we have corrupted data

if (current_tstate == prev_tstate) {

Py_DECREF(interpreter_threads);

PyErr_Format(PyExc_RuntimeError,

"Thread list cycle detected at address 0x%lx (corrupted remote memory)",

current_tstate);

set_exception_cause(self, PyExc_RuntimeError,

"Thread list cycle detected (corrupted remote memory)");

Py_CLEAR(result);

goto exit;

}

// Thread was skipped due to mode filtering, continue to next thread

continue;

}

// This was an actual error

Py_DECREF(interpreter_threads);

set_exception_cause(self, PyExc_RuntimeError, "Failed to unwind stack for thread");

Py_CLEAR(result);

goto exit;

}

if (PyList_Append(interpreter_threads, frame_info) == -1) {

Py_DECREF(frame_info);

Py_DECREF(interpreter_threads);

set_exception_cause(self, PyExc_RuntimeError, "Failed to append thread frame info");

Py_CLEAR(result);

goto exit;

}

Py_DECREF(frame_info);

// If targeting specific thread or only active thread, process just one

if (self->tstate_addr || self->only_active_thread) {

break;

}

// Create the InterpreterInfo StructSequence

RemoteDebuggingState *state = RemoteDebugging_GetStateFromObject((PyObject*)self);

PyObject *interpreter_info = PyStructSequence_New(state->InterpreterInfo_Type);

if (!interpreter_info) {

Py_DECREF(interpreter_threads);

set_exception_cause(self, PyExc_MemoryError, "Failed to create InterpreterInfo");

Py_CLEAR(result);

goto exit;

}

PyObject *interp_id = PyLong_FromLongLong(interpreter_id);

if (!interp_id) {

Py_DECREF(interpreter_threads);

Py_DECREF(interpreter_info);

set_exception_cause(self, PyExc_MemoryError, "Failed to create interpreter ID");

Py_CLEAR(result);

goto exit;

}

PyStructSequence_SetItem(interpreter_info, 0, interp_id); // steals reference

PyStructSequence_SetItem(interpreter_info, 1, interpreter_threads); // steals reference

// Add this interpreter to the result list

if (PyList_Append(result, interpreter_info) == -1) {

Py_DECREF(interpreter_info);

set_exception_cause(self, PyExc_RuntimeError, "Failed to append interpreter info");

Py_CLEAR(result);

goto exit;

}

Py_DECREF(interpreter_info);

next_interpreter:

// Get the next interpreter address

current_interpreter = GET_MEMBER(uintptr_t, interp_state_buffer,

self->debug_offsets.interpreter_state.next);

// If we're targeting a specific thread, stop after first interpreter

if (self->tstate_addr != 0) {

break;

}

exit:

// Invalidate cache entries for threads not seen in this sample.

// Only do this every 1024 iterations to avoid performance overhead.

if (self->cache_frames && result) {

if (++self->stale_invalidation_counter >= 1024) {

self->stale_invalidation_counter = 0;

frame_cache_invalidate_stale(self, result);

}

_Py_RemoteDebug_ClearCache(&self->handle);

return result;

}

/*[clinic input]

@permit_long_summary

@critical_section

_remote_debugging.RemoteUnwinder.get_all_awaited_by

Get all tasks and their awaited_by relationships from the remote process.

This provides a tree structure showing which tasks are waiting for

other tasks.

For each task, returns:

1. The call stack frames leading to where the task is currently

executing

2. The name of the task

3. A list of tasks that this task is waiting for, with their own

frames/names/etc

Returns a list of [frames, task_name, subtasks] where:

- frames: List of (func_name, filename, lineno) showing the call

stack

- task_name: String identifier for the task

- subtasks: List of tasks being awaited by this task, in same format

Raises:

RuntimeError: If AsyncioDebug section is not available in the

remote process

MemoryError: If memory allocation fails

OSError: If reading from the remote process fails

Example output:

[

# Task c2_root waiting for two subtasks

[

# Call stack of c2_root

[("c5", "script.py", 10), ("c4", "script.py", 14)],

"c2_root",

[

# First subtask (sub_main_2) and what it's waiting for

[

[("c1", "script.py", 23)],

"sub_main_2",

[...]

# Second subtask and its waiters

[...]

]

[clinic start generated code]*/

static PyObject *

_remote_debugging_RemoteUnwinder_get_all_awaited_by_impl(RemoteUnwinderObject *self)

/*[clinic end generated code: output=6a49cd345e8aec53 input=c22bfee0612e0b69]*/

{

if (ensure_async_debug_offsets(self) < 0) {

return NULL;

}

if (refresh_generation_caches_for_interpreter(self, self->interpreter_addr) < 0) {

return NULL;

}

PyObject *result = PyList_New(0);

if (result == NULL) {

set_exception_cause(self, PyExc_MemoryError, "Failed to create awaited_by result list");

goto result_err;

}

// Process all threads

if (iterate_threads(self, process_thread_for_awaited_by, result) < 0) {

goto result_err;

}

uintptr_t head_addr = self->interpreter_addr

+ (uintptr_t)self->async_debug_offsets.asyncio_interpreter_state.asyncio_tasks_head;

// On top of a per-thread task lists used by default by asyncio to avoid

// contention, there is also a fallback per-interpreter list of tasks;

// any tasks still pending when a thread is destroyed will be moved to the

// per-interpreter task list. It's unlikely we'll find anything here, but

// interesting for debugging.

if (append_awaited_by(self, 0, head_addr, result))

{

set_exception_cause(self, PyExc_RuntimeError, "Failed to append interpreter awaited_by in get_all_awaited_by");

goto result_err;

}

_Py_RemoteDebug_ClearCache(&self->handle);

return result;

result_err:

_Py_RemoteDebug_ClearCache(&self->handle);

Py_XDECREF(result);

return NULL;

}

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