[Python-checkins] [2.7] bpo-22851: Fix a segfault when accessing generator.gi_frame.f_restricted. (GH-9348)

[Serhiy Storchaka]

https://github.com/python/cpython/commit/68ddb59417ee0b0dedf5c8b66a304138c9ce0a63
commit: 68ddb59417ee0b0dedf5c8b66a304138c9ce0a63
branch: 2.7
author: Zackery Spytz <zspytz at gmail.com>
committer: Serhiy Storchaka <storchaka at gmail.com>
date: 2018-10-13T12:25:05+03:00
summary:

[2.7] bpo-22851: Fix a segfault when accessing generator.gi_frame.f_restricted. (GH-9348)

Frame's field f_tstate is NULL when the generator is exhausted.

files:
A Misc/NEWS.d/next/Core and Builtins/2018-09-17-04-41-42.bpo-22851.0hsJPh.rst
M Include/frameobject.h
M Lib/test/test_generators.py

diff --git a/Include/frameobject.h b/Include/frameobject.h
index 843908159ddb..34603794c655 100644
--- a/Include/frameobject.h
+++ b/Include/frameobject.h
@@ -56,7 +56,7 @@ PyAPI_DATA(PyTypeObject) PyFrame_Type;
 
 #define PyFrame_Check(op) (Py_TYPE(op) == &PyFrame_Type)
 #define PyFrame_IsRestricted(f) \
-	((f)->f_builtins != (f)->f_tstate->interp->builtins)
+	((f)->f_tstate && (f)->f_builtins != (f)->f_tstate->interp->builtins)
 
 PyAPI_FUNC(PyFrameObject *) PyFrame_New(PyThreadState *, PyCodeObject *,
                                        PyObject *, PyObject *);
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 0f7bf19abb8c..10285f67a2c6 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -1877,6 +1877,16 @@ def printsolution(self, x):
 
 """
 
+crash_test = """
+>>> def foo(): yield
+>>> gen = foo()
+>>> gen.next()
+>>> print gen.gi_frame.f_restricted  # This would segfault.
+False
+
+"""
+
+
 __test__ = {"tut":      tutorial_tests,
             "pep":      pep_tests,
             "email":    email_tests,
@@ -1886,6 +1896,7 @@ def printsolution(self, x):
             "weakref":  weakref_tests,
             "coroutine":  coroutine_tests,
             "refleaks": refleaks_tests,
+            "crash": crash_test,
             }
 
 # Magic test name that regrtest.py invokes *after* importing this module.
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-09-17-04-41-42.bpo-22851.0hsJPh.rst b/Misc/NEWS.d/next/Core and Builtins/2018-09-17-04-41-42.bpo-22851.0hsJPh.rst
new file mode 100644
index 000000000000..c5f524940085
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-09-17-04-41-42.bpo-22851.0hsJPh.rst	
@@ -0,0 +1,2 @@
+Fix a segfault when accessing ``generator.gi_frame.f_restricted`` when the
+generator is exhausted.  Patch by Zackery Spytz.