https://github.com/python/cpython/commit/a14cccbaa4787860ede0945ffaf67cf14b34c8e2
commit: a14cccbaa4787860ede0945ffaf67cf14b34c8e2
branch: main
author: Neko Asakura <[email protected]>
committer: vstinner <[email protected]>
date: 2026-11-04T19:57:14Z
summary:
gh-161288: Fix perf trampoline crash on UBSan builds (#161294)
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2026-11-03-20-28-15.gh-issue-161288.LikC_U.rst
M Include/pyport.h
M Lib/test/test_perf_profiler.py
M Lib/test/test_samply_profiler.py
M Python/perf_trampoline.c
diff --git a/Include/pyport.h b/Include/pyport.h
index 3de7fb3d317521..9cbc9170d01238 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -579,6 +579,9 @@ extern "C" {
# define _Py_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
# endif
# endif
+# if __has_feature(undefined_behavior_sanitizer)
+# define _Py_NO_SANITIZE_FUNCTION __attribute__((no_sanitize("function")))
+# endif
#elif defined(__GNUC__)
# if defined(__SANITIZE_ADDRESS__)
# define _Py_ADDRESS_SANITIZER
@@ -606,6 +609,9 @@ extern "C" {
#ifndef _Py_NO_SANITIZE_MEMORY
# define _Py_NO_SANITIZE_MEMORY
#endif
+#ifndef _Py_NO_SANITIZE_FUNCTION
+# define _Py_NO_SANITIZE_FUNCTION
+#endif
#ifndef _Py_MSAN_UNPOISON
# define _Py_MSAN_UNPOISON(PTR, SIZE)
#endif
diff --git a/Lib/test/test_perf_profiler.py b/Lib/test/test_perf_profiler.py
index 7fe16116b00b99..0ebc0792cfc822 100644
--- a/Lib/test/test_perf_profiler.py
+++ b/Lib/test/test_perf_profiler.py
@@ -17,10 +17,10 @@
if not support.has_subprocess_support:
raise unittest.SkipTest("test module requires subprocess")
-if support.check_sanitizer(address=True, memory=True, ub=True, function=True):
+if support.check_sanitizer(address=True, memory=True, function=False):
# gh-109580: Skip the test because it does crash randomly if Python is
# built with ASAN.
- raise unittest.SkipTest("test crash randomly on ASAN/MSAN/UBSAN build")
+ raise unittest.SkipTest("test crash randomly on ASAN/MSAN build")
def supports_trampoline_profiling():
diff --git a/Lib/test/test_samply_profiler.py b/Lib/test/test_samply_profiler.py
index 6c3be8f38ed0c0..b9ac6586f4f7f5 100644
--- a/Lib/test/test_samply_profiler.py
+++ b/Lib/test/test_samply_profiler.py
@@ -14,10 +14,10 @@
if not support.has_subprocess_support:
raise unittest.SkipTest("test module requires subprocess")
-if support.check_sanitizer(address=True, memory=True, ub=True, function=True):
+if support.check_sanitizer(address=True, memory=True, function=False):
# gh-109580: Skip the test because it does crash randomly if Python is
# built with ASAN.
- raise unittest.SkipTest("test crash randomly on ASAN/MSAN/UBSAN build")
+ raise unittest.SkipTest("test crash randomly on ASAN/MSAN build")
def supports_trampoline_profiling():
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2026-11-03-20-28-15.gh-issue-161288.LikC_U.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2026-11-03-20-28-15.gh-issue-161288.LikC_U.rst
new file mode 100644
index 00000000000000..4cf8201d02ce7c
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2026-11-03-20-28-15.gh-issue-161288.LikC_U.rst
@@ -0,0 +1,3 @@
+Fix a crash in the perf trampoline (:option:`-X perf <-X>`) on builds with
+clang's ``-fsanitize=function``, which ``-fsanitize=undefined`` enables
+since clang 17.
diff --git a/Python/perf_trampoline.c b/Python/perf_trampoline.c
index 431ac2c3a778ed..5e6f3b213eb81f 100644
--- a/Python/perf_trampoline.c
+++ b/Python/perf_trampoline.c
@@ -434,7 +434,8 @@ compile_trampoline(void)
return code_arena_new_code(perf_code_arena);
}
-static PyObject *
+// gh-161288: the trampoline has no -fsanitize=function type signature
+static PyObject * _Py_NO_SANITIZE_FUNCTION
py_trampoline_evaluator(PyThreadState *ts, _PyInterpreterFrame *frame,
int throw)
{
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