gh-139275: Fix compilation of Modules/_remote_debugging_module.c when the system doesn't have process_vm_readv

Misc/NEWS.d/next/Core_and_Builtins/2025-09-24-17-32-52.gh-issue-139275.novrqf.rst

@@ -0,0 +1,2 @@
+Fix compilation problems in ``_remote_debugging_module.c`` when the system
+doesn't have ``process_vm_readv``. Patch by Pablo Galindo

Modules/_remote_debugging_module.c

@@ -824,7 +824,7 @@ _Py_RemoteDebug_GetAsyncioDebugAddress(proc_handle_t* handle)
         PyErr_SetString(PyExc_RuntimeError, "Failed to find the AsyncioDebug section in the process.");
         _PyErr_ChainExceptions1(exc);
     }
-#elif defined(__linux__)
+#elif defined(__linux__) && HAVE_PROCESS_VM_READV
     // On Linux, search for asyncio debug in executable or DLL
     address = search_linux_map_for_section(handle, "AsyncioDebug", "python");
     if (address == 0) {
@@ -2453,6 +2453,137 @@ process_frame_chain(
     return 0;
 }
 
+<<<<<<< Updated upstream
+=======
+static int
+get_thread_status(RemoteUnwinderObject *unwinder, uint64_t tid, uint64_t pthread_id) {
+#if defined(__APPLE__) && TARGET_OS_OSX
+   if (unwinder->thread_id_offset == 0) {
+        uint64_t *tids = (uint64_t *)PyMem_Malloc(MAX_NATIVE_THREADS * sizeof(uint64_t));
+        if (!tids) {
+            PyErr_NoMemory();
+            return -1;
+        }
+        int n = proc_pidinfo(unwinder->handle.pid, PROC_PIDLISTTHREADS, 0, tids, MAX_NATIVE_THREADS * sizeof(uint64_t)) / sizeof(uint64_t);
+        if (n <= 0) {
+            PyMem_Free(tids);
+            return THREAD_STATE_UNKNOWN;
+        }
+        uint64_t min_offset = UINT64_MAX;
+        for (int i = 0; i < n; i++) {
+            uint64_t offset = tids[i] - pthread_id;
+            if (offset < min_offset) {
+                min_offset = offset;
+            }
+        }
+        unwinder->thread_id_offset = min_offset;
+        PyMem_Free(tids);
+    }
+    struct proc_threadinfo ti;
+    uint64_t tid_with_offset = pthread_id + unwinder->thread_id_offset;
+    if (proc_pidinfo(unwinder->handle.pid, PROC_PIDTHREADINFO, tid_with_offset, &ti, sizeof(ti)) != sizeof(ti)) {
+        return THREAD_STATE_UNKNOWN;
+    }
+    if (ti.pth_run_state == TH_STATE_RUNNING) {
+        return THREAD_STATE_RUNNING;
+    }
+    return THREAD_STATE_IDLE;
+#elif defined(__linux__) && HAVE_PROCESS_VM_READV
+    char stat_path[256];
+    char buffer[2048] = "";
+
+    snprintf(stat_path, sizeof(stat_path), "/proc/%d/task/%lu/stat", unwinder->handle.pid, tid);
+
+    int fd = open(stat_path, O_RDONLY);
+    if (fd == -1) {
+        return THREAD_STATE_UNKNOWN;
+    }
+
+    if (read(fd, buffer, 2047) == 0) {
+        close(fd);
+        return THREAD_STATE_UNKNOWN;
+    }
+    close(fd);
+
+    char *p = strchr(buffer, ')');
+    if (!p) {
+        return THREAD_STATE_UNKNOWN;
+    }
+
+    p += 2;  // Skip ") "
+    if (*p == ' ') {
+        p++;
+    }
+
+    switch (*p) {
+        case 'R':  // Running
+            return THREAD_STATE_RUNNING;
+        case 'S':  // Interruptible sleep
+        case 'D':  // Uninterruptible sleep
+        case 'T':  // Stopped
+        case 'Z':  // Zombie
+        case 'I':  // Idle kernel thread
+            return THREAD_STATE_IDLE;
+        default:
+            return THREAD_STATE_UNKNOWN;
+    }
+#elif defined(MS_WINDOWS)
+    ULONG n;
+    NTSTATUS status = NtQuerySystemInformation(
+        SystemProcessInformation,
+        unwinder->win_process_buffer,
+        unwinder->win_process_buffer_size,
+        &n
+    );
+    if (status == STATUS_INFO_LENGTH_MISMATCH) {
+        // Buffer was too small so we reallocate a larger one and try again.
+        unwinder->win_process_buffer_size = n;
+        PVOID new_buffer = PyMem_Realloc(unwinder->win_process_buffer, n);
+        if (!new_buffer) {
+            return -1;
+        }
+        unwinder->win_process_buffer = new_buffer;
+        return get_thread_status(unwinder, tid, pthread_id);
+    }
+    if (status != STATUS_SUCCESS) {
+        return -1;
+    }
+
+    SYSTEM_PROCESS_INFORMATION *pi = (SYSTEM_PROCESS_INFORMATION *)unwinder->win_process_buffer;
+    while ((ULONG)(ULONG_PTR)pi->UniqueProcessId != unwinder->handle.pid) {
+        if (pi->NextEntryOffset == 0) {
+            // We didn't find the process
+            return -1;
+        }
+        pi = (SYSTEM_PROCESS_INFORMATION *)(((BYTE *)pi) + pi->NextEntryOffset);
+    }
+
+    SYSTEM_THREAD_INFORMATION *ti = (SYSTEM_THREAD_INFORMATION *)((char *)pi + sizeof(SYSTEM_PROCESS_INFORMATION));
+    for (Py_ssize_t i = 0; i < pi->NumberOfThreads; i++, ti++) {
+        if (ti->ClientId.UniqueThread == (HANDLE)tid) {
+            return ti->ThreadState != WIN32_THREADSTATE_RUNNING ? THREAD_STATE_IDLE : THREAD_STATE_RUNNING;
+        }
+    }
+
+    return -1;
+#else
+    return THREAD_STATE_UNKNOWN;
+#endif
+}
+
+typedef struct {
+    unsigned int initialized:1;
+    unsigned int bound:1;
+    unsigned int unbound:1;
+    unsigned int bound_gilstate:1;
+    unsigned int active:1;
+    unsigned int finalizing:1;
+    unsigned int cleared:1;
+    unsigned int finalized:1;
+    unsigned int :24;
+} _thread_status;
+
+>>>>>>> Stashed changes
 static PyObject*
 unwind_stack_for_thread(
     RemoteUnwinderObject *unwinder,

Python/remote_debug.h

@@ -891,7 +891,7 @@ _Py_RemoteDebug_GetPyRuntimeAddress(proc_handle_t* handle)
             handle->pid);
         _PyErr_ChainExceptions1(exc);
     }
-#elif defined(__linux__)
+#elif defined(__linux__) && HAVE_PROCESS_VM_READV
     // On Linux, search for 'python' in executable or DLL
     address = search_linux_map_for_section(handle, "PyRuntime", "python");
     if (address == 0) {