* bpo-36389: _PyObject_CheckConsistency() available in release mode (GH-16612)
bpo-36389, bpo-38376: The _PyObject_CheckConsistency() function is
now also available in release mode. For example, it can be used to
debug a crash in the visit_decref() function of the GC.
Modify the following functions to also work in release mode:
* _PyDict_CheckConsistency()
* _PyObject_CheckConsistency()
* _PyType_CheckConsistency()
* _PyUnicode_CheckConsistency()
Other changes:
* _PyMem_IsPtrFreed(ptr) now also returns 1 if ptr is NULL
(equals to 0).
* _PyBytesWriter_CheckConsistency() now returns 1 and is only used
with assert().
* Reorder _PyObject_Dump() to write safe fields first, and only
attempt to render repr() at the end.
(cherry picked from commit 6876257eaa)
* bpo-36389: Fix _PyBytesWriter in release mode (GH-16624)
Fix _PyBytesWriter API when Python is built in release mode with
assertions.
(cherry picked from commit 60ec6efd96)
* bpo-38070: Enhance visit_decref() debug trace (GH-16631)
subtract_refs() now pass the parent object to visit_decref() which
pass it to _PyObject_ASSERT(). So if the "is freed" assertion fails,
the parent is used in debug trace, rather than the freed object. The
parent object is more likely to contain useful information. Freed
objects cannot be inspected are are displayed as "<object at xxx is
freed>" with no other detail.
(cherry picked from commit 4d5f94b8cd)
* Fix also a typo in PYMEM_DEADBYTE macro comment
* bpo-36389: Add newline to _PyObject_AssertFailed() (GH-16629)
Add a newline between the verbose object dump and the Py_FatalError()
logs for readability.
(cherry picked from commit 7775349895)
* [bpo-38379](https://bugs.python.org/issue38379): when a finalizer resurrects an object,
nothing is actually collected in this run of gc.
Change the stats to relect that truth.
(cherry picked from commit ecbf35f933)
Co-authored-by: Tim Peters <tim.peters@gmail.com>
https://bugs.python.org/issue38379
Automerge-Triggered-By: @pablogsal
Fix a bug due to the interaction of weakrefs and the cyclic garbage
collector. We must clear any weakrefs in garbage in order to prevent
their callbacks from executing and causing a crash.
(cherry picked from commit bcda460baf)
Co-authored-by: Neil Schemenauer <nas-github@arctrix.com>
In debug mode, visit_decref() now calls _PyObject_IsFreed() to ensure
that the object is not freed. If it's freed, the program fails with
an assertion error and Python dumps informations about the freed
object.
(cherry picked from commit d91d4de317)
Co-authored-by: Victor Stinner <vstinner@redhat.com>
It is now allowed to add new fields at the end of the PyTypeObject struct without having to allocate a dedicated compatibility flag in tp_flags.
This will reduce the risk of running out of bits in the 32-bit tp_flags value.
* sys.unraisablehook: add 'err_msg' field to UnraisableHookArgs.
* Use _PyErr_WriteUnraisableMsg() in _ctypes _DictRemover_call()
and gc delete_garbage().
* Add a 'runtime' variable to Py_FinalizeEx() rather than working
directly on the global variable _PyRuntime
* Add a 'runtime' parameter to _PyGC_Fini(), _PyGILState_Fini()
and call_ll_exitfuncs()
* Add _PyObject_ASSERT_FROM() and _PyObject_ASSERT_FAILED_MSG()
macros.
* PyObject_GC_Track() now calls _PyObject_ASSERT_FAILED_MSG(),
instead of Py_FatalError(), if the object is already tracked, to
dump more information on error.
* _PyObject_GC_TRACK() no longer checks if the object is already
tracked at runtime, use an assertion instead for best performances;
PyObject_GC_Track() still checks at runtime.
* pycore_object.h now includes pycore_pystate.h.
* Convert _PyObject_GC_TRACK() and _PyObject_GC_UNTRACK() macros to
inline functions.
Replace assert() with _PyObject_ASSERT() in Modules/gcmodule.c
to dump the faulty object on assertion failure to ease debugging.
Fix also indentation of a large comment.
Initial patch written by David Malcolm.
Co-Authored-By: David Malcolm <dmalcolm@redhat.com>
Changes:
* Add _PyObject_AssertFailed() function.
* Add _PyObject_ASSERT() and _PyObject_ASSERT_WITH_MSG() macros.
* gc_decref(): replace assert() with _PyObject_ASSERT_WITH_MSG() to
dump the faulty object if the assertion fails.
_PyObject_AssertFailed() calls:
* _PyMem_DumpTraceback(): try to log the traceback where the object
memory has been allocated if tracemalloc is enabled.
* _PyObject_Dump(): log repr(obj).
* Py_FatalError(): log the current Python traceback.
_PyObject_AssertFailed() uses _PyObject_IsFreed() heuristic to check
if the object memory has been freed by a debug hook on Python memory
allocators.
Initial patch written by David Malcolm.
Co-Authored-By: David Malcolm <dmalcolm@redhat.com>
* Failure in adding to gc.garbage is no longer fatal.
* An exception in tp_clear() no longer lead to crash (though tp_clear() should not leave exceptions).
* Fixed a leak when the GC fails to add an object with __del__ into
the gc.garbage list.
* PyGC_Collect() can now be called when an exception is set and
preserves it.
* Fixed an undefined behavior with comparing a dead pointer with NULL.
* Use wider types (int => Py_ssize_t) to avoid integer overflows.
* Fix gc.get_freeze_count(): use Py_ssize_t type rather than int, since gc_list_size() returns a Py_ssize_t.
Freeze all the objects tracked by gc - move them to a permanent generation
and ignore all the future collections. This can be used before a POSIX
fork() call to make the gc copy-on-write friendly or to speed up collection.
* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals
Other globals are excluded (see globals.txt and check-c-globals.py).
* group the (stateful) runtime globals into various topical structs
* consolidate the topical structs under a single top-level _PyRuntimeState struct
* add a check-c-globals.py script that helps identify runtime globals
Other globals are excluded (see globals.txt and check-c-globals.py).
Issue #28858: The change b9c9691c72c5 introduced a regression. It seems like
_PyObject_CallArg1() uses more stack memory than
PyObject_CallFunctionObjArgs().
* PyObject_CallFunctionObjArgs(func, NULL) => _PyObject_CallNoArg(func)
* PyObject_CallFunctionObjArgs(func, arg, NULL) => _PyObject_CallArg1(func, arg)
PyObject_CallFunctionObjArgs() allocates 40 bytes on the C stack and requires
extra work to "parse" C arguments to build a C array of PyObject*.
_PyObject_CallNoArg() and _PyObject_CallArg1() are simpler and don't allocate
memory on the C stack.
This change is part of the fastcall project. The change on listsort() is
related to the issue #23507.
Tested on macOS 10.11 dtrace, Ubuntu 16.04 SystemTap, and libbcc.
Largely based by an initial patch by Jesús Cea Avión, with some
influence from Dave Malcolm's SystemTap patch and Nikhil Benesch's
unification patch.
Things deliberately left out for simplicity:
- ustack helpers, I have no way of testing them at this point since
they are Solaris-specific
- PyFrameObject * in function__entry/function__return, this is
SystemTap-specific
- SPARC support
- dynamic tracing
- sys module dtrace facility introspection
All of those might be added later.
threading.Lock.acquire(), threading.RLock.acquire() and socket operations now
use a monotonic clock, instead of the system clock, when a timeout is used.
Issue #21435: Segfault in gc with cyclic trash
Changed the iteration logic in finalize_garbage() to tolerate objects vanishing
from the list as a side effect of executing a finalizer.
PyObject_Calloc(), _PyObject_GC_Calloc(). bytes(int) and bytearray(int) are now
using ``calloc()`` instead of ``malloc()`` for large objects which is faster
and use less memory (until the bytearray buffer is filled with data).
Victor Stinner
Pablo Galindo
Miss Islington (bot)
Inada Naoki
Antoine Pitrou
Victor Stinner
Quan Tian
INADA Naoki
Serhiy Storchaka
Yury Selivanov
Victor Stinner
brainfvck
Eric Snow
Łukasz Langa
Antoine Pitrou
Tim Peters