bpo-31719: Fix test_regrtest.test_crashed() on s390x (#3912)
Add a new _testcapi._read_null() function to crash Python in a
reliable way on s390x.
On s390x, ctypes.string_at(0) returns an empty string rather than
crashing.
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index ef474e0..25df3ed 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -1960,6 +1960,6 @@
Use SuppressCrashReport() to prevent a crash report from popping up.
"""
- import ctypes
+ import _testcapi
with SuppressCrashReport():
- ctypes.string_at(0)
+ _testcapi._read_null()
diff --git a/Lib/test/test_regrtest.py b/Lib/test/test_regrtest.py
index 264c74d..aae2743 100644
--- a/Lib/test/test_regrtest.py
+++ b/Lib/test/test_regrtest.py
@@ -543,6 +543,8 @@
testname)
self.assertEqual(output.splitlines(), all_methods)
+ @unittest.skipIf(sys.platform.startswith('aix'),
+ "support._crash_python() doesn't work on AIX")
def test_crashed(self):
# Any code which causes a crash
code = 'import test.support; test.support._crash_python()'
diff --git a/Misc/NEWS.d/next/Tests/2017-10-06-22-37-38.bpo-31719.gHyrV3.rst b/Misc/NEWS.d/next/Tests/2017-10-06-22-37-38.bpo-31719.gHyrV3.rst
new file mode 100644
index 0000000..a06c526
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2017-10-06-22-37-38.bpo-31719.gHyrV3.rst
@@ -0,0 +1,3 @@
+Fix test_regrtest.test_crashed() on s390x. Add a new _testcapi._read_null()
+function to crash Python in a reliable way on s390x. On s390x,
+ctypes.string_at(0) returns an empty string rather than crashing.
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 7691b51..5902de0 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -2566,6 +2566,22 @@
#endif
+/* Read memory from NULL (address 0) to raise a SIGSEGV or SIGBUS signal
+ depending on the platform. This function is used by
+ test.support._crash_python() to "crash" Python. */
+static PyObject *
+read_null(PyObject *self, PyObject *args)
+{
+ volatile int *x;
+ volatile int y;
+
+ x = NULL;
+ y = *x;
+ return PyLong_FromLong(y);
+
+}
+
+
static PyMethodDef TestMethods[] = {
{"raise_exception", raise_exception, METH_VARARGS},
{"set_errno", set_errno, METH_VARARGS},
@@ -2685,6 +2701,7 @@
#ifdef W_STOPCODE
{"W_STOPCODE", py_w_stopcode, METH_VARARGS},
#endif
+ {"_read_null", (PyCFunction)read_null, METH_NOARGS},
{NULL, NULL} /* sentinel */
};