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Title: bz2.BZ2File.__init__() cannot be called twice with non-existent file
Type: crash Stage: resolved
Components: Interpreter Core Versions: Python 2.7
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: nadeem.vawda Nosy List: Level, nadeem.vawda, ned.deily, python-dev, serhiy.storchaka, vajrasky, vstinner
Priority: normal Keywords: patch

Created on 2013-12-03 18:51 by Level, last changed 2022-04-11 14:57 by admin. This issue is now closed.

File name Uploaded Description Edit
fix_segfault_in_bz2_init_non_existent_file.patch vajrasky, 2013-12-04 04:18 review
Messages (8)
msg205137 - (view) Author: Matthew Bergin (Level) Date: 2013-12-03 18:51
[level@<removed> fuzz]# cat
import bz2
obj = bz2.BZ2File('/tmp/fileName')
[level@<removed> fuzz]# gdb --args python
GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1)
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
Reading symbols from /usr/bin/python...(no debugging symbols found)...done.
Missing separate debuginfos, use: debuginfo-install python-2.6.6-37.el6_4.i686 python-2.6.6-37.el6_4.x86_64
(gdb) r
Starting program: /usr/bin/python
[Thread debugging using libthread_db enabled]
Traceback (most recent call last):
  File "", line 3, in <module>
IOError: [Errno 2] No such file or directory: 'fileName'

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7a98170 in PyFile_DecUseCount () from /usr/lib64/
msg205143 - (view) Author: Ned Deily (ned.deily) * (Python committer) Date: 2013-12-03 19:56
Sorry, the Python 2.6 series is now officially retired.  As of 2.6.9, "All official maintenance for Python 2.6, including security patches, has ended."  If you can reproduce the problem with a currently supported version of Python, such as Python 2.7.6 or 3.3.3, please reopen with similar documentation.
msg205149 - (view) Author: STINNER Victor (vstinner) * (Python committer) Date: 2013-12-03 21:01
I can reproduce the issue with Python 2.7. The problem is that BZ2File.__init__() doesn't reset the object when __init__() is called twice.

For example, the following script fails with "too many open files" error, before the previous file is not called:
import bz2
obj = bz2.BZ2File('bla.bz2')
for loop in range(1024*10):

By the way, why do you call __init__() twice? Why not creating a new object?

BZ2File was rewritten in pure Python in Python 3.3. Python 3.3+ is not affected by this issue.
msg205151 - (view) Author: Matthew Bergin (Level) Date: 2013-12-03 21:04
I was fuzzing the interpreter otherwise it would init itself
msg205159 - (view) Author: Nadeem Vawda (nadeem.vawda) * (Python committer) Date: 2013-12-03 21:31
It appears that this *does* affect 2.7 (though not 3.2, 3.3 or 3.4, fortunately):

    ~/src/cpython/2.7☿ gdb --ex run --args ./python -c 'import bz2; obj = bz2.BZ2File("/dev/null"); obj.__init__("")'
    «... snip banner ...»
    Starting program: /home.u/nadeem/src/cpython/2.7/./python -c import\ bz2\;\ obj\ =\ bz2.BZ2File\(\"/dev/null\"\)\;\ obj.__init__\(\"\"\)
    [Thread debugging using libthread_db enabled]
    Using host libthread_db library "/lib/x86_64-linux-gnu/".
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    IOError: [Errno 2] No such file or directory: ''

    Program received signal SIGSEGV, Segmentation fault.
    0x0000000000431d3e in PyFile_DecUseCount (fobj=0x0) at Objects/fileobject.c:89
    89          fobj->unlocked_count--;
msg205194 - (view) Author: Vajrasky Kok (vajrasky) * Date: 2013-12-04 04:18
Here is the preliminary patch.
msg205568 - (view) Author: Roundup Robot (python-dev) (Python triager) Date: 2013-12-08 14:49
New changeset 55a748f6e396 by Nadeem Vawda in branch '2.7':
Closes #19878: Fix segfault in bz2 module.
msg205834 - (view) Author: Roundup Robot (python-dev) (Python triager) Date: 2013-12-10 16:23
New changeset 3337298f5c75 by Nadeem Vawda in branch '2.7':
Skip test for #19878 on Windows.
Date User Action Args
2022-04-11 14:57:54adminsetgithub: 64077
2013-12-10 16:23:19python-devsetmessages: + msg205834
2013-12-08 14:49:31python-devsetstatus: open -> closed

nosy: + python-dev
messages: + msg205568

resolution: fixed
stage: needs patch -> resolved
2013-12-04 04:18:53vajraskysetfiles: + fix_segfault_in_bz2_init_non_existent_file.patch
title: bz2.BZ2File.__init__() cannot be called twice -> bz2.BZ2File.__init__() cannot be called twice with non-existent file
nosy: + vajrasky

messages: + msg205194

keywords: + patch
2013-12-03 21:31:05nadeem.vawdasetnosy: + nadeem.vawda
messages: + msg205159

assignee: nadeem.vawda
stage: needs patch
2013-12-03 21:04:58Levelsetmessages: + msg205151
2013-12-03 21:01:56vstinnersetstatus: closed -> open

title: PyFile_DecUseCount() SIGSEGV -> bz2.BZ2File.__init__() cannot be called twice
nosy: + vstinner, serhiy.storchaka
versions: + Python 2.7, - Python 2.6
messages: + msg205149
resolution: rejected -> (no value)
stage: resolved -> (no value)
2013-12-03 19:56:19ned.deilysetstatus: open -> closed

nosy: + ned.deily
messages: + msg205143

resolution: rejected
stage: resolved
2013-12-03 18:55:03Levelsettype: crash
2013-12-03 18:51:08Levelcreate