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crash when deleting one pair from tee() #57663

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crash when deleting one pair from tee()#57663
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serhiy-storchaka
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extension-modulesC modules in the Modules dirtype-crashA hard crash of the interpreter, possibly with a core dump

Description

@PyryP
PyryP
mannequin
opened on Nov 22, 2011
BPO 13454
Nosy @birkenfeld, @rhettinger, @amauryfa, @pitrou, @vstinner, @ezio-melotti, @serhiy-storchaka
Files
  • itertools_tee_nonrecursive_clear.patch
  • itertools_tee_nonrecursive_clear_2.patch
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = 'https://github.com/serhiy-storchaka'
closed_at = <Date 2013-01-25.11:36:17.711>
created_at = <Date 2011-11-22.16:10:44.540>
labels = ['extension-modules', 'type-crash']
title = 'crash when deleting one pair from tee()'
updated_at = <Date 2013-01-26.09:56:33.793>
user = 'https://bugs.python.org/PyryP'

    bugs.python.org fields:

    activity = <Date 2013-01-26.09:56:33.793>
actor = 'python-dev'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2013-01-25.11:36:17.711>
closer = 'serhiy.storchaka'
components = ['Extension Modules']
creation = <Date 2011-11-22.16:10:44.540>
creator = 'PyryP'
dependencies = []
files = ['27578', '28467']
hgrepos = []
issue_num = 13454
keywords = ['patch', 'needs review']
message_count = 14.0
messages = ['148124', '148125', '148126', '148127', '172890', '172905', '172916', '174473', '178324', '178370', '178399', '179466', '180568', '180649']
nosy_count = 9.0
nosy_names = ['georg.brandl', 'rhettinger', 'amaury.forgeotdarc', 'pitrou', 'vstinner', 'ezio.melotti', 'python-dev', 'PyryP', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue13454'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3', 'Python 3.4']

    Activity

    1. PyryP commented on Nov 22, 2011

      @PyryP
      PyryPmannequin
      on Nov 22, 2011
      MannequinAuthor

      Running the following results in a Segmentation fault on Ubuntu 11.10 64-bit with both python and python3.

      from itertools import *
c = count()
a,b = tee(c)
for i in range(10000000):
 next(a)
del(b)
    2. PyryP
      added
      type-crashA hard crash of the interpreter, possibly with a core dump
      on Nov 22, 2011

    3. vstinner commented on Nov 22, 2011

      @vstinner
      vstinner
      on Nov 22, 2011
      Member

      tee() uses a linked-list of teedataobject. This list is destroyed by recursive calls to teedataobject_dealloc().

      Extract of the gdb trace:

      #5 0x08171a8e in teedataobject_clear (tdo=0xad21b394) at ./Modules/itertoolsmodule.c:412
      #6 0x08171b39 in teedataobject_dealloc (tdo=0xad21b394) at ./Modules/itertoolsmodule.c:421
      #7 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad21b394>) at Objects/object.c:1676
      #8 0x08171b16 in teedataobject_clear (tdo=0xad21b274) at ./Modules/itertoolsmodule.c:413
      #9 0x08171b39 in teedataobject_dealloc (tdo=0xad21b274) at ./Modules/itertoolsmodule.c:421
      #10 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad21b274>) at Objects/object.c:1676
      #11 0x08171b16 in teedataobject_clear (tdo=0xad21b154) at ./Modules/itertoolsmodule.c:413
      #12 0x08171b39 in teedataobject_dealloc (tdo=0xad21b154) at ./Modules/itertoolsmodule.c:421
      #13 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad21b154>) at Objects/object.c:1676
      #14 0x08171b16 in teedataobject_clear (tdo=0xad21b034) at ./Modules/itertoolsmodule.c:413
      #15 0x08171b39 in teedataobject_dealloc (tdo=0xad21b034) at ./Modules/itertoolsmodule.c:421
      #16 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad21b034>) at Objects/object.c:1676
      #17 0x08171b16 in teedataobject_clear (tdo=0xad292ed4) at ./Modules/itertoolsmodule.c:413
      #18 0x08171b39 in teedataobject_dealloc (tdo=0xad292ed4) at ./Modules/itertoolsmodule.c:421
      #19 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad292ed4>) at Objects/object.c:1676
      #20 0x08171b16 in teedataobject_clear (tdo=0xad292db4) at ./Modules/itertoolsmodule.c:413
      #21 0x08171b39 in teedataobject_dealloc (tdo=0xad292db4) at ./Modules/itertoolsmodule.c:421
      #22 0x0805ed3d in _Py_Dealloc (op=<itertools.tee_dataobject at remote 0xad292db4>) at Objects/object.c:1676
      #23 0x08171b16 in teedataobject_clear (tdo=0xad292c94) at ./Modules/itertoolsmodule.c:413

    4. ezio-melotti commented on Nov 22, 2011

      @ezio-melotti
      ezio-melotti
      on Nov 22, 2011
      Member

      Confirmed on py3k, it doesn't seem to happen with smaller values.

    5. ezio-melotti
      added
      extension-modulesC modules in the Modules dir
      on Nov 22, 2011

    6. amauryfa commented on Nov 22, 2011

      @amauryfa
      amauryfa
      on Nov 22, 2011
      Contributor

      Also, a check for NULL would not hurt in tee_next():

      diff -r 1e0e821d2626 Modules/itertoolsmodule.c
--- a/Modules/itertoolsmodule.c	Fri Nov 04 22:17:45 2011 +0100
+++ b/Modules/itertoolsmodule.c	Tue Nov 22 17:24:42 2011 +0100
@@ -475,6 +475,8 @@
 
     if (to->index >= LINKCELLS) {
         link = teedataobject_jumplink(to->dataobj);
+        if (link == NULL)
+            return NULL;
         Py_DECREF(to->dataobj);
         to->dataobj = (teedataobject *)link;
         to->index = 0;

    7. serhiy-storchaka commented on Oct 14, 2012

      @serhiy-storchaka
      serhiy-storchaka
      on Oct 14, 2012
      Member

      Here is a patch (tests included). Thank Pyry for report, Victor and Amaury for analysis.

      Maybe I picked up the poor names for iterators? May be exhausted and unexhausted would be better? Feel free to correct me.

    8. pitrou commented on Oct 14, 2012

      @pitrou
      pitrou
      on Oct 14, 2012
      Member

      Serhiy, I only see a test in your patch, no actual modification to itertools.

    9. serhiy-storchaka commented on Oct 14, 2012

      @serhiy-storchaka
      serhiy-storchaka
      on Oct 14, 2012
      Member

      Oh, I worked on it in a different directory. Fortunately I found a temporary copy and I do not have to write all code again. Sorry.

    10. serhiy-storchaka commented on Nov 1, 2012

      @serhiy-storchaka
      serhiy-storchaka
      on Nov 1, 2012
      Member

      Please review.

    11. serhiy-storchaka commented on Dec 27, 2012

      @serhiy-storchaka
      serhiy-storchaka
      on Dec 27, 2012
      Member

      Ping.

    12. serhiy-storchaka
      self-assigned this
      on Dec 27, 2012

    13. birkenfeld commented on Dec 28, 2012

      @birkenfeld
      birkenfeld
      on Dec 28, 2012
      Member

      The patch replaces a

       Py_CLEAR(tdo->nextlink)

with a construct that does, basically, something like this several times:

 Py_DECREF(tdo->nextlink)
 tdo->nextlink

      which is what leads to the issues that Py_CLEAR is supposed to prevent. Therefore I think this patch is not correct.

    14. serhiy-storchaka commented on Dec 28, 2012

      @serhiy-storchaka
      serhiy-storchaka
      on Dec 28, 2012
      Member

      Good point. Here is updated patch.

    15. serhiy-storchaka commented on Jan 9, 2013

      @serhiy-storchaka
      serhiy-storchaka
      on Jan 9, 2013
      Member

      If no one objects I will commit this next week.

    16. python-dev commented on Jan 25, 2013

      @python-dev
      python-devmannequin
      on Jan 25, 2013
      Mannequin

      New changeset f7e14a1af609 by Serhiy Storchaka in branch '3.2':
      Issue bpo-13454: Fix a crash when deleting an iterator created by itertools.tee()
      http://hg.python.org/cpython/rev/f7e14a1af609

      New changeset eff2a7346243 by Serhiy Storchaka in branch '3.3':
      Issue bpo-13454: Fix a crash when deleting an iterator created by itertools.tee()
      http://hg.python.org/cpython/rev/eff2a7346243

      New changeset 02d7a127fdfb by Serhiy Storchaka in branch 'default':
      Issue bpo-13454: Fix a crash when deleting an iterator created by itertools.tee()
      http://hg.python.org/cpython/rev/02d7a127fdfb

      New changeset 62f2d3f6015e by Serhiy Storchaka in branch '2.7':
      Issue bpo-13454: Fix a crash when deleting an iterator created by itertools.tee()
      http://hg.python.org/cpython/rev/62f2d3f6015e

    17. serhiy-storchaka
      closed this as completedon Jan 25, 2013

    18. python-dev commented on Jan 26, 2013

      @python-dev
      python-devmannequin
      on Jan 26, 2013
      Mannequin

      New changeset 4ee8d38398d4 by Serhiy Storchaka in branch '2.7':
      Optimize the test for issue bpo-13454.
      http://hg.python.org/cpython/rev/4ee8d38398d4

      New changeset d391b2849a51 by Serhiy Storchaka in branch '3.2':
      Optimize the test for issue bpo-13454.
      http://hg.python.org/cpython/rev/d391b2849a51

      New changeset 2258b4d89c9f by Serhiy Storchaka in branch '3.3':
      Optimize the test for issue bpo-13454.
      http://hg.python.org/cpython/rev/2258b4d89c9f

      New changeset 1f57fb5e1e8e by Serhiy Storchaka in branch 'default':
      Optimize the test for issue bpo-13454.
      http://hg.python.org/cpython/rev/1f57fb5e1e8e

    19. ezio-melotti
      transferred this issue fromon Apr 10, 2022
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