From 978a1aacabc3bc3ca06b6a7ce60954cfd9298e98 Mon Sep 17 00:00:00 2001 From: Rok Mandeljc Date: Mon, 22 Sep 2025 13:10:54 +0200 Subject: [PATCH] gh-139231: Fix estimation of available stack size for recursion limit on macOS On macOS, use `pthread_get_stackaddr_np()` and `pthread_get_stacksize_np()` to determine the stack address and size (used by code handling the recursion limit), rather than falling back to conservative hard-coded default of 4 MB. --- Python/ceval.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Python/ceval.c b/Python/ceval.c index 7abbc9e9fd12b6..0ccaacaf3ed5b1 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -451,6 +451,13 @@ _Py_InitializeRecursionLimits(PyThreadState *tstate) SetThreadStackGuarantee(&guarantee); _tstate->c_stack_hard_limit = ((uintptr_t)low) + guarantee + _PyOS_STACK_MARGIN_BYTES; _tstate->c_stack_soft_limit = _tstate->c_stack_hard_limit + _PyOS_STACK_MARGIN_BYTES; +#elif defined(__APPLE__) + pthread_t this_thread = pthread_self(); + void *stack_addr = pthread_get_stackaddr_np(this_thread); // top of the stack + size_t stack_size = pthread_get_stacksize_np(this_thread); + _tstate->c_stack_top = (uintptr_t)stack_addr; + _tstate->c_stack_hard_limit = _tstate->c_stack_top - stack_size; + _tstate->c_stack_soft_limit = _tstate->c_stack_hard_limit + _PyOS_STACK_MARGIN_BYTES; #else uintptr_t here_addr = _Py_get_machine_stack_pointer(); /// XXX musl supports HAVE_PTHRED_GETATTR_NP, but the resulting stack size