Description

assignee = 'https://github.com/serhiy-storchaka'
closed_at = <Date 2017-09-26.20:16:27.494>
created_at = <Date 2017-05-11.21:10:21.469>
labels = ['extension-modules', '3.7', 'type-crash']
title = 'itertools.groupby() can fail a C assert()'
updated_at = <Date 2017-09-26.20:16:27.493>
user = 'https://github.com/arigo'

activity = <Date 2017-09-26.20:16:27.493>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2017-09-26.20:16:27.494>
closer = 'serhiy.storchaka'
components = ['Extension Modules']
creation = <Date 2017-05-11.21:10:21.469>
creator = 'arigo'
dependencies = []
files = []
hgrepos = []
issue_num = 30347
keywords = ['patch']
message_count = 8.0
messages = ['293517', '293519', '293549', '293579', '302948', '303062', '303065', '303071']
nosy_count = 3.0
nosy_names = ['arigo', 'rhettinger', 'serhiy.storchaka']
pr_nums = ['1557', '3770', '3772']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue30347'
versions = ['Python 2.7', 'Python 3.6', 'Python 3.7']

Activity

1. arigo commented on May 11, 2017

   

   arigomannequin

   on May 11, 2017

   MannequinAuthor

   More actions

   This triggers an assert() failure on debug-mode Python (or a leak in release Python):

   from itertools import groupby
   
   def f(n):
       print("enter:", n)
       if n == 5:
           list(b)
       print("leave:", n)
       return n != 6
   
   for (k, b) in groupby(range(10), f):
       print(list(b))

   With current trunk we get: python: ./Modules/itertoolsmodule.c:303: _grouper_next: Assertion `gbo->currkey == NULL' failed.
2. arigo

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   3.7 (EOL)end of lifeend of life

   type-crashA hard crash of the interpreter, possibly with a core dumpA hard crash of the interpreter, possibly with a core dump

   on May 11, 2017
3. serhiy-storchaka

   added

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   and removed

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   on May 11, 2017
4. serhiy-storchaka

   assigned

   rhettinger

   on May 11, 2017
5. rhettinger commented on May 11, 2017

   

   rhettinger

   on May 11, 2017

   Contributor

   More actions

   Do you have a suggested fix?
6. serhiy-storchaka commented on May 12, 2017

   

   serhiy-storchaka

   on May 12, 2017

   Member

   More actions

   PR 1557 implements the simplest fix -- remove the assert and use Py_XSETREF() instead of simple assignment. Since the resulting code in _grouper_next() is identical to the code in groupby_next(), it was shared between these two functions.
7. rhettinger commented on May 12, 2017

   

   rhettinger

   on May 12, 2017

   Contributor

   More actions

   At first glance, the suggested PR looks fine. Unless there is a rush, I would like to hold-off spend more time thinking about bpo-30346 before moving forward with this one.
8. rhettinger

   assigned

   serhiy-storchaka

   and unassigned

   rhettinger

   on Sep 25, 2017
9. serhiy-storchaka commented on Sep 25, 2017

   

   serhiy-storchaka

   on Sep 25, 2017

   Member

   More actions

   Hmm, the sole bpo-30346 is not enough for fixing this crash. I don't know if there is a simpler fix based on bpo-30346, but since PR 1557 removes the code duplication I'm going to merge it in any case.
10. serhiy-storchaka commented on Sep 26, 2017

    

    serhiy-storchaka

    on Sep 26, 2017

    Member

    More actions

    New changeset c740e4f by Serhiy Storchaka in branch 'master':
    bpo-30347: Stop crashes when concurrently iterate over itertools.groupby() iterators. (bpo-1557)
    c740e4f
11. serhiy-storchaka commented on Sep 26, 2017

    

    serhiy-storchaka

    on Sep 26, 2017

    Member

    More actions

    New changeset 69b2dc8 by Serhiy Storchaka (Miss Islington (bot)) in branch '3.6':
    [3.6] bpo-30347: Stop crashes when concurrently iterate over itertools.groupby() iterators. (GH-1557) (bpo-3770)
    69b2dc8
12. serhiy-storchaka commented on Sep 26, 2017

    

    serhiy-storchaka

    on Sep 26, 2017

    Member

    More actions

    New changeset d0b9dc3 by Serhiy Storchaka in branch '2.7':
    [2.7] bpo-30347: Stop crashes when concurrently iterate over itertools.groupby() iterators. (GH-1557). (bpo-3772)
    d0b9dc3
13. serhiy-storchaka

    closed this as completedon Sep 26, 2017
14. ezio-melotti

    transferred this issue fromon Apr 10, 2022

Issue actions