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GH-95909: Make _PyArg_Parser initialization thread safe (GH-95958)

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Kumar Aditya 2022-08-16 23:52:14 +05:30 committed by GitHub
parent 48174fa0b9
commit 9b30b965f0
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 48 additions and 12 deletions
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4
Include/internal/pycore_runtime.h
View File

@ -14,6 +14,9 @@ extern "C" {
#include "pycore_interp.h" // PyInterpreterState
#include "pycore_unicodeobject.h" // struct _Py_unicode_runtime_ids
struct _getargs_runtime_state {
PyThread_type_lock mutex;
};
/* ceval state */
@ -114,6 +117,7 @@ typedef struct pyruntimestate {
struct _ceval_runtime_state ceval;
struct _gilstate_runtime_state gilstate;
struct _getargs_runtime_state getargs;
PyPreConfig preconfig;

29
Python/getargs.c
View File

@ -1974,15 +1974,10 @@ new_kwtuple(const char * const *keywords, int total, int pos)
}
static int
parser_init(struct _PyArg_Parser *parser)
_parser_init(struct _PyArg_Parser *parser)
{
const char * const *keywords = parser->keywords;
assert(keywords != NULL);
if (parser->initialized) {
assert(parser->kwtuple != NULL);
return 1;
}
assert(parser->pos == 0 &&
(parser->format == NULL || parser->fname == NULL) &&
parser->custom_msg == NULL &&
@ -2035,6 +2030,28 @@ parser_init(struct _PyArg_Parser *parser)
return 1;
}
static int
parser_init(struct _PyArg_Parser *parser)
{
// volatile as it can be modified by other threads
// and should not be optimized or reordered by compiler
if (*((volatile int *)&parser->initialized)) {
assert(parser->kwtuple != NULL);
return 1;
}
PyThread_acquire_lock(_PyRuntime.getargs.mutex, WAIT_LOCK);
// Check again if another thread initialized the parser
// while we were waiting for the lock.
if (*((volatile int *)&parser->initialized)) {
assert(parser->kwtuple != NULL);
PyThread_release_lock(_PyRuntime.getargs.mutex);
return 1;
}
int ret = _parser_init(parser);
PyThread_release_lock(_PyRuntime.getargs.mutex);
return ret;
}
static void
parser_clear(struct _PyArg_Parser *parser)
{

27
Python/pystate.c
View File

@ -57,7 +57,7 @@ _Py_COMP_DIAG_POP
static int
alloc_for_runtime(PyThread_type_lock *plock1, PyThread_type_lock *plock2,
PyThread_type_lock *plock3)
PyThread_type_lock *plock3, PyThread_type_lock *plock4)
{
/* Force default allocator, since _PyRuntimeState_Fini() must
use the same allocator than this function. */
@ -82,11 +82,20 @@ alloc_for_runtime(PyThread_type_lock *plock1, PyThread_type_lock *plock2,
return -1;
}
PyThread_type_lock lock4 = PyThread_allocate_lock();
if (lock4 == NULL) {
PyThread_free_lock(lock1);
PyThread_free_lock(lock2);
PyThread_free_lock(lock3);
return -1;
}
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
*plock1 = lock1;
*plock2 = lock2;
*plock3 = lock3;
*plock4 = lock4;
return 0;
}
@ -97,7 +106,8 @@ init_runtime(_PyRuntimeState *runtime,
Py_ssize_t unicode_next_index,
PyThread_type_lock unicode_ids_mutex,
PyThread_type_lock interpreters_mutex,
PyThread_type_lock xidregistry_mutex)
PyThread_type_lock xidregistry_mutex,
PyThread_type_lock getargs_mutex)
{
if (runtime->_initialized) {
Py_FatalError("runtime already initialized");
@ -119,6 +129,8 @@ init_runtime(_PyRuntimeState *runtime,
runtime->xidregistry.mutex = xidregistry_mutex;
runtime->getargs.mutex = getargs_mutex;
// Set it to the ID of the main thread of the main interpreter.
runtime->main_thread = PyThread_get_thread_ident();
@ -141,8 +153,8 @@ _PyRuntimeState_Init(_PyRuntimeState *runtime)
// is called multiple times.
Py_ssize_t unicode_next_index = runtime->unicode_ids.next_index;
PyThread_type_lock lock1, lock2, lock3;
if (alloc_for_runtime(&lock1, &lock2, &lock3) != 0) {
PyThread_type_lock lock1, lock2, lock3, lock4;
if (alloc_for_runtime(&lock1, &lock2, &lock3, &lock4) != 0) {
return _PyStatus_NO_MEMORY();
}
@ -152,7 +164,7 @@ _PyRuntimeState_Init(_PyRuntimeState *runtime)
memcpy(runtime, &initial, sizeof(*runtime));
}
init_runtime(runtime, open_code_hook, open_code_userdata, audit_hook_head,
unicode_next_index, lock1, lock2, lock3);
unicode_next_index, lock1, lock2, lock3, lock4);
return _PyStatus_OK();
}
@ -172,6 +184,7 @@ _PyRuntimeState_Fini(_PyRuntimeState *runtime)
FREE_LOCK(runtime->interpreters.mutex);
FREE_LOCK(runtime->xidregistry.mutex);
FREE_LOCK(runtime->unicode_ids.lock);
FREE_LOCK(runtime->getargs.mutex);
#undef FREE_LOCK
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
@ -194,6 +207,7 @@ _PyRuntimeState_ReInitThreads(_PyRuntimeState *runtime)
int reinit_interp = _PyThread_at_fork_reinit(&runtime->interpreters.mutex);
int reinit_xidregistry = _PyThread_at_fork_reinit(&runtime->xidregistry.mutex);
int reinit_unicode_ids = _PyThread_at_fork_reinit(&runtime->unicode_ids.lock);
int reinit_getargs = _PyThread_at_fork_reinit(&runtime->getargs.mutex);
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
@ -204,7 +218,8 @@ _PyRuntimeState_ReInitThreads(_PyRuntimeState *runtime)
if (reinit_interp < 0
|| reinit_main_id < 0
|| reinit_xidregistry < 0
|| reinit_unicode_ids < 0)
|| reinit_unicode_ids < 0
|| reinit_getargs < 0)
{
return _PyStatus_ERR("Failed to reinitialize runtime locks");