tkinter.createfilehandler dumps core

[romberg]

BPO	692416
Nosy	@loewis

^{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/loewis'
closed_at = <Date 2003-03-03.21:28:01.000>
created_at = <Date 2003-02-24.18:54:11.000>
labels = ['expert-tkinter']
title = 'tkinter.createfilehandler dumps core'
updated_at = <Date 2003-03-03.21:28:01.000>
user = 'https://bugs.python.org/romberg'

bugs.python.org fields:

activity = <Date 2003-03-03.21:28:01.000>
actor = 'nnorwitz'
assignee = 'loewis'
closed = True
closed_date = None
closer = None
components = ['Tkinter']
creation = <Date 2003-02-24.18:54:11.000>
creator = 'romberg'
dependencies = []
files = []
hgrepos = []
issue_num = 692416
keywords = []
message_count = 5.0
messages = ['14798', '14799', '14800', '14801', '14802']
nosy_count = 3.0
nosy_names = ['loewis', 'nnorwitz', 'romberg']
pr_nums = []
priority = 'high'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue692416'
versions = ['Python 2.3']

[romberg]

This small example probably uses an invalid
mask and the filedescriptor for a dummy file. But
I'm seeing this core dump even when using
a correct mask and sockets. This is with 2.3a2.

>>> import Tkinter
>>> tk = Tkinter.Tk()
>>> fp = open('foo', 'w')
>>> def foo():
...     pass
... 
>>> Tkinter._tkinter.createfilehandler(fp.fileno(), 0, foo)
Segmentation fault (core dumped)

Here is the traceback:

#0 Tkapp_CreateFileHandler (self=0x0, args=0x1) at
Modules/_tkinter.c:2205
#1 0x080f279a in PyCFunction_Call (func=0x0,
arg=0x40730a68, kw=0x0)
at Objects/methodobject.c:108
#2 0x080a73cd in call_function (pp_stack=0xbffff2ec,
oparg=1)
at Python/ceval.c:3285
#3 0x080a58ed in eval_frame (f=0x815700c) at
Python/ceval.c:2041
#4 0x080a630c in PyEval_EvalCodeEx (co=0x40569160,
globals=0x0, locals=0x1,
args=0x815700c, argcount=0, kws=0x0, kwcount=0,
defs=0x0, defcount=0,
closure=0x0) at Python/ceval.c:2588
#5 0x080a8af7 in PyEval_EvalCode (co=0x1, globals=0x1,
locals=0x1)
at Python/ceval.c:535
#6 0x080cf25b in run_node (n=0x4015f4e8,
filename=0x1 <Address 0x1 out of bounds>,
globals=0x1, locals=0x1,
flags=0x1) at Python/pythonrun.c:1105
#7 0x080ce7ae in PyRun_InteractiveOneFlags (fp=0x1,
filename=0x80f530a "<stdin>", flags=0xbffff4d8) at
Python/pythonrun.c:609
#8 0x080ce5a3 in PyRun_InteractiveLoopFlags
(fp=0x421271c0,
filename=0x80f530a "<stdin>", flags=0x40569160) at
Python/pythonrun.c:542
#9 0x080cfae2 in PyRun_AnyFileExFlags (fp=0x421271c0,
filename=0x80f530a "<stdin>", closeit=0,
flags=0xbffff4d8)
at Python/pythonrun.c:505
#10 0x08054909 in Py_Main (argc=0, argv=0xbffff544) at
Modules/main.c:446
#11 0x0805448b in main (argc=1, argv=0x1) at
Modules/python.c:23
#12 0x420158d4 in __libc_start_main () from
/lib/i686/libc.so.6

[nnorwitz]

Logged In: YES
user_id=33168

Confirmed the core dump on Linux with Tk 8.3. Hopefully
Martin will be back soon. If not I'll try to take a look.

[nnorwitz]

Logged In: YES
user_id=33168

The problem is that CHECK_TCL_APPARTMENT is called in
Tkapp_CreateFileHandler() and Tkapp_DeleteFileHandler().
The CHECK_TCL_APPARTMENT macro uses self which is NULL when
called through the module. Checking if (self == NULL)
before calling CHECK_TCL_APPARTMENT would prevent the crash,
but I'm not certain this is correct.

As a workaround, you should be able to access create/delete
filehandler through the instance:

   w.tk.createfilehandler(...)

instead of Tkinter.createfilehandler(...).

[loewis]

Logged In: YES
user_id=21627

This is now fixed in _tkinter.c 1.150 (also for
createtimerhandler). In threaded Tcl, createfilehandler
can't really work if invoked from a different thread, so you
will have to use a non-threaded Tcl to continue to use
_tkinter.createfilehandler.

[nnorwitz]

Logged In: YES
user_id=33168

Also fixed for deletefilehandler.
Checked in as:

• Modules/_tkinter.c 1.151
• Misc/NEWS 1.688