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[3.6] bpo-30604: Move co_extra_freefuncs to interpreter state to avoid crashes in threads (#2015)

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* Move co_extra_freefuncs to interpreter state to avoid crashes in
multi-threaded scenarios involving deletion of code objects

* Don't require that extra be zero initialized

* Build test list instead of defining empty test class

* Ensure extra is always assigned on success

* Keep the old fields in the thread state object, just don't use them
Add new linked list of code extra objects on a per-interpreter basis
  so that interpreter state size isn't changed

* Rename __PyCodeExtraState_Get and add comment about it going away in 3.7
Fix sort order of import's in test_code.py

* Remove an extraneous space

* Remove docstrings for comments

* Touch up formatting

* Fix casing of coextra local

* Fix casing of another variable

* Prefix PyCodeExtraState with __ to match C API for getting it

* Update NEWS file for bpo-30604
This commit is contained in:
Dino Viehland 2017-06-12 18:46:35 -07:00 • committed by Ned Deily
parent f59cac4b64
commit 2997fec01e
6 changed files with 180 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

8
Python/ceval.c
View file

@ -5453,14 +5453,14 @@ _Py_GetDXProfile(PyObject *self, PyObject *args)
Py_ssize_t
_PyEval_RequestCodeExtraIndex(freefunc free)
{
PyThreadState *tstate = PyThreadState_Get();
__PyCodeExtraState *state = __PyCodeExtraState_Get();
Py_ssize_t new_index;
if (tstate->co_extra_user_count == MAX_CO_EXTRA_USERS - 1) {
if (state->co_extra_user_count == MAX_CO_EXTRA_USERS - 1) {
return -1;
}
new_index = tstate->co_extra_user_count++;
tstate->co_extra_freefuncs[new_index] = free;
new_index = state->co_extra_user_count++;
state->co_extra_freefuncs[new_index] = free;
return new_index;
}

44
Python/pystate.c
View file

@ -55,6 +55,7 @@ static int autoTLSkey = -1;
#endif
static PyInterpreterState *interp_head = NULL;
static __PyCodeExtraState *coextra_head = NULL;
/* Assuming the current thread holds the GIL, this is the
PyThreadState for the current thread. */
@ -73,6 +74,12 @@ PyInterpreterState_New(void)
PyMem_RawMalloc(sizeof(PyInterpreterState));
if (interp != NULL) {
__PyCodeExtraState* coextra = PyMem_RawMalloc(sizeof(__PyCodeExtraState));
if (coextra == NULL) {
PyMem_RawFree(interp);
return NULL;
}
HEAD_INIT();
#ifdef WITH_THREAD
if (head_mutex == NULL)
@ -92,6 +99,8 @@ PyInterpreterState_New(void)
interp->importlib = NULL;
interp->import_func = NULL;
interp->eval_frame = _PyEval_EvalFrameDefault;
coextra->co_extra_user_count = 0;
coextra->interp = interp;
#ifdef HAVE_DLOPEN
#if HAVE_DECL_RTLD_NOW
interp->dlopenflags = RTLD_NOW;
@ -103,6 +112,8 @@ PyInterpreterState_New(void)
HEAD_LOCK();
interp->next = interp_head;
interp_head = interp;
coextra->next = coextra_head;
coextra_head = coextra;
HEAD_UNLOCK();
}
@ -147,9 +158,10 @@ void
PyInterpreterState_Delete(PyInterpreterState *interp)
{
PyInterpreterState **p;
__PyCodeExtraState **pextra;
zapthreads(interp);
HEAD_LOCK();
for (p = &interp_head; ; p = &(*p)->next) {
for (p = &interp_head; /* N/A */; p = &(*p)->next) {
if (*p == NULL)
Py_FatalError(
"PyInterpreterState_Delete: invalid interp");
@ -159,6 +171,18 @@ PyInterpreterState_Delete(PyInterpreterState *interp)
if (interp->tstate_head != NULL)
Py_FatalError("PyInterpreterState_Delete: remaining threads");
*p = interp->next;
for (pextra = &coextra_head; ; pextra = &(*pextra)->next) {
if (*pextra == NULL)
Py_FatalError(
"PyInterpreterState_Delete: invalid extra");
__PyCodeExtraState* extra = *pextra;
if (extra->interp == interp) {
*pextra = extra->next;
PyMem_RawFree(extra);
break;
}
}
HEAD_UNLOCK();
PyMem_RawFree(interp);
#ifdef WITH_THREAD
@ -224,7 +248,6 @@ new_threadstate(PyInterpreterState *interp, int init)
tstate->coroutine_wrapper = NULL;
tstate->in_coroutine_wrapper = 0;
tstate->co_extra_user_count = 0;
tstate->async_gen_firstiter = NULL;
tstate->async_gen_finalizer = NULL;
@ -548,6 +571,23 @@ PyThreadState_Swap(PyThreadState *newts)
return oldts;
}
__PyCodeExtraState*
__PyCodeExtraState_Get() {
PyInterpreterState* interp = PyThreadState_Get()->interp;
HEAD_LOCK();
for (__PyCodeExtraState* cur = coextra_head; cur != NULL; cur = cur->next) {
if (cur->interp == interp) {
HEAD_UNLOCK();
return cur;
}
}
HEAD_UNLOCK();
Py_FatalError("__PyCodeExtraState_Get: no code state for interpreter");
return NULL;
}
/* An extension mechanism to store arbitrary additional per-thread state.
PyThreadState_GetDict() returns a dictionary that can be used to hold such
state; the caller should pick a unique key and store its state there. If