https://github.com/python/cpython/commit/0a160bf14c4848f50539e52e2de486c641d122a2
commit: 0a160bf14c4848f50539e52e2de486c641d122a2
branch: main
author: Bénédikt Tran <10796600+picn...@users.noreply.github.com>
committer: picnixz <10796600+picn...@users.noreply.github.com>
date: 2025-05-18T10:16:10+02:00
summary:
gh-133157: remove usage of `_Py_NO_SANITIZE_UNDEFINED` in `faulthandler`
(#134047)
In `faulthandler_sigfpe()`, instead of using 1/0 arithmetic, we explicitly
raise SIGFPE.
We also remove `faulthandler._read_null()` since reading from NULL is an
undefined
behavior and `faulthandler` should not check for low-level C undefined
behaviors.
files:
M Lib/test/test_faulthandler.py
M Modules/faulthandler.c
diff --git a/Lib/test/test_faulthandler.py b/Lib/test/test_faulthandler.py
index 371c63adce9412..2fb963f52e5138 100644
--- a/Lib/test/test_faulthandler.py
+++ b/Lib/test/test_faulthandler.py
@@ -166,29 +166,6 @@ def check_windows_exception(self, code, line_number,
name_regex, **kw):
fatal_error = 'Windows fatal exception: %s' % name_regex
self.check_error(code, line_number, fatal_error, **kw)
- @unittest.skipIf(sys.platform.startswith('aix'),
- "the first page of memory is a mapped read-only on AIX")
- def test_read_null(self):
- if not MS_WINDOWS:
- self.check_fatal_error("""
- import faulthandler
- faulthandler.enable()
- faulthandler._read_null()
- """,
- 3,
- # Issue #12700: Read NULL raises SIGILL on Mac OS X Lion
- '(?:Segmentation fault'
- '|Bus error'
- '|Illegal instruction)')
- else:
- self.check_windows_exception("""
- import faulthandler
- faulthandler.enable()
- faulthandler._read_null()
- """,
- 3,
- 'access violation')
-
@skip_segfault_on_android
def test_sigsegv(self):
self.check_fatal_error("""
diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index d49ce794d88674..c94f4f66366170 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -1069,18 +1069,6 @@ faulthandler_suppress_crash_report(void)
#endif
}
-static PyObject* _Py_NO_SANITIZE_UNDEFINED
-faulthandler_read_null(PyObject *self, PyObject *args)
-{
- volatile int *x;
- volatile int y;
-
- faulthandler_suppress_crash_report();
- x = NULL;
- y = *x;
- return PyLong_FromLong(y);
-
-}
static void
faulthandler_raise_sigsegv(void)
@@ -1158,23 +1146,12 @@ faulthandler_fatal_error_c_thread(PyObject *self,
PyObject *args)
Py_RETURN_NONE;
}
-static PyObject* _Py_NO_SANITIZE_UNDEFINED
+static PyObject*
faulthandler_sigfpe(PyObject *self, PyObject *Py_UNUSED(dummy))
{
faulthandler_suppress_crash_report();
-
- /* Do an integer division by zero: raise a SIGFPE on Intel CPU, but not on
- PowerPC. Use volatile to disable compile-time optimizations. */
- volatile int x = 1, y = 0, z;
- z = x / y;
-
- /* If the division by zero didn't raise a SIGFPE (e.g. on PowerPC),
- raise it manually. */
raise(SIGFPE);
-
- /* This line is never reached, but we pretend to make something with z
- to silence a compiler warning. */
- return PyLong_FromLong(z);
+ Py_UNREACHABLE();
}
static PyObject *
@@ -1316,10 +1293,6 @@ static PyMethodDef module_methods[] = {
"Unregister the handler of the signal "
"'signum' registered by register().")},
#endif
- {"_read_null", faulthandler_read_null, METH_NOARGS,
- PyDoc_STR("_read_null($module, /)\n--\n\n"
- "Read from NULL, raise "
- "a SIGSEGV or SIGBUS signal depending on the platform.")},
{"_sigsegv", faulthandler_sigsegv, METH_VARARGS,
PyDoc_STR("_sigsegv($module, release_gil=False, /)\n--\n\n"
"Raise a SIGSEGV signal.")},
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