From: Sam Gross <colesbury@gmail.com>
Date: Tue, 11 Mar 2025 14:33:23 +0000 (-0400)
Subject: gh-130396: Fix thread sanitizer crashes on stack overflow tests (gh-130966)
X-Git-Tag: v3.14.0a6~79
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4162bc133b21ccb06d3589bd69ddb7bb248c58d2;p=thirdparty%2FPython%2Fcpython.git

gh-130396: Fix thread sanitizer crashes on stack overflow tests (gh-130966)

Thread sanitizer will often crash if a test uses more than half the
stack.
---

diff --git a/Python/ceval.c b/Python/ceval.c
index a702d296e224..f9089d7f11f2 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -392,7 +392,12 @@ _Py_InitializeRecursionLimits(PyThreadState *tstate)
     if (err == 0) {
         uintptr_t base = ((uintptr_t)stack_addr) + guard_size;
         _tstate->c_stack_top = base + stack_size;
+#ifdef _Py_THREAD_SANITIZER
+        // Thread sanitizer crashes if we use a bit more than half the stack.
+        _tstate->c_stack_soft_limit = base + (stack_size / 2);
+#else
         _tstate->c_stack_soft_limit = base + PYOS_STACK_MARGIN_BYTES * 2;
+#endif
         _tstate->c_stack_hard_limit = base + PYOS_STACK_MARGIN_BYTES;
         assert(_tstate->c_stack_soft_limit < here_addr);
         assert(here_addr < _tstate->c_stack_top);