Skip to content

gh-117657: Fix data races reported by TSAN on interp->threads.main #118865

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 4 commits into from
May 10, 2024
Merged

gh-117657: Fix data races reported by TSAN on interp->threads.main #118865

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
50cf12b
Fix data races reported by TSAN on `interp->threads.main`
mpage May 9, 2024
f412a0c
📜🤖 Added by blurb_it.
blurb-it[bot] May 9, 2024
7c9e286
Merge branch 'main' into gh-117657-tsan-is-running-main
mpage May 9, 2024
17d8622
Remove corresponding suppressions
mpage May 9, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2024-05-09-19-47-12.gh-issue-117657.Vn0Yey.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix data races on the field that stores a pointer to the interpreter's main thread that occur in free-threaded builds.
31 changes: 20 additions & 11 deletions Python/pystate.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1038,6 +1038,17 @@ _PyInterpreterState_DeleteExceptMain(_PyRuntimeState *runtime)
}
#endif

static inline void
set_main_thread(PyInterpreterState *interp, PyThreadState *tstate)
{
_Py_atomic_store_ptr_relaxed(&interp->threads.main, tstate);
}

static inline PyThreadState *
get_main_thread(PyInterpreterState *interp)
{
return _Py_atomic_load_ptr_relaxed(&interp->threads.main);
}

int
_PyInterpreterState_SetRunningMain(PyInterpreterState *interp)
Expand All @@ -1052,21 +1063,22 @@ _PyInterpreterState_SetRunningMain(PyInterpreterState *interp)
"current tstate has wrong interpreter");
return -1;
}
interp->threads.main = tstate;
set_main_thread(interp, tstate);

return 0;
}

void
_PyInterpreterState_SetNotRunningMain(PyInterpreterState *interp)
{
assert(interp->threads.main == current_fast_get());
interp->threads.main = NULL;
assert(get_main_thread(interp) == current_fast_get());
set_main_thread(interp, NULL);
}

int
_PyInterpreterState_IsRunningMain(PyInterpreterState *interp)
{
if (interp->threads.main != NULL) {
if (get_main_thread(interp) != NULL) {
return 1;
}
// Embedders might not know to call _PyInterpreterState_SetRunningMain(),
Expand All @@ -1082,18 +1094,15 @@ int
_PyThreadState_IsRunningMain(PyThreadState *tstate)
{
PyInterpreterState *interp = tstate->interp;
if (interp->threads.main != NULL) {
return tstate == interp->threads.main;
}
// See the note in _PyInterpreterState_IsRunningMain() about
// possible false negatives here for embedders.
return 0;
return get_main_thread(interp) == tstate;
}

int
_PyInterpreterState_FailIfRunningMain(PyInterpreterState *interp)
{
if (interp->threads.main != NULL) {
if (get_main_thread(interp) != NULL) {
PyErr_SetString(PyExc_InterpreterError,
"interpreter already running");
return -1;
Expand All @@ -1105,8 +1114,8 @@ void
_PyInterpreterState_ReinitRunningMain(PyThreadState *tstate)
{
PyInterpreterState *interp = tstate->interp;
if (interp->threads.main != tstate) {
interp->threads.main = NULL;
if (get_main_thread(interp) != tstate) {
set_main_thread(interp, NULL);
}
}

Expand Down
Loading