python segfault for-loop + print

[Erik Lovlie]

Python segfaults for a fairly simple python for-loop. I realize that a segfault shouldn't happen anyway, and that it likely means there is a bug in python, but I am posting it here since I was running IPython. I also am not sure that what I am typing makes sense, as I don't know python much at all.

Steps to reproduce:
1. start ipython
2. type:
for i in range: [enter]
print 42 [enter]

Observe: segfault (backtrace attached below). Happens every time.

Version info:

IPython 0.10
Python 2.5.4 (r254:67916, Oct 1 2009, 01:51:32)
Linux 2.6.9-42.ELsmp #1 SMP Wed Jul 12 23:32:02 EDT 2006 x86_64 x86_64 x86_64 GNU/Linux

Backtrace:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 182894237888 (LWP 25515)]
0x00000031e32691a5 in free () from /lib64/tls/libc.so.6
(gdb) bt
#0 0x00000031e32691a5 in free () from /lib64/tls/libc.so.6
#1 0x0000002a96d58d6a in py_remove_history (self=0x20, args=0x20) at /arm/scratch/camdan01/depot/python/python/2.5.4/rhe4-x86_64/Modules/readline.c:318
#2 0x000000000048afa2 in PyEval_EvalFrameEx (f=0x92a8d0, throwflag=9611920) at Python/ceval.c:3612
#3 0x000000000048c861 in PyEval_EvalCodeEx (co=0x2a974c1a08, globals=0x935bf0, locals=0x20, args=0x91e618, argcount=3, kws=0x91e630, kwcount=0, defs=0x2a97721410, defcount=2, closure=0x0)
    at Python/ceval.c:2875
#4 0x000000000048abdd in PyEval_EvalFrameEx (f=0x91e470, throwflag=-1754119512) at Python/ceval.c:3707
#5 0x000000000048c861 in PyEval_EvalCodeEx (co=0x2a974c1288, globals=0x935bf0, locals=0x20, args=0x928298, argcount=2, kws=0x9282a8, kwcount=0, defs=0x2a97717de8, defcount=1, closure=0x0)
    at Python/ceval.c:2875
#6 0x000000000048abdd in PyEval_EvalFrameEx (f=0x928110, throwflag=-1754121208) at Python/ceval.c:3707
#7 0x000000000048c861 in PyEval_EvalCodeEx (co=0x2a974b9f30, globals=0x935bf0, locals=0x20, args=0x91c790, argcount=2, kws=0x91c7a0, kwcount=0, defs=0x2a97717da8, defcount=1, closure=0x0)
    at Python/ceval.c:2875
#8 0x000000000048abdd in PyEval_EvalFrameEx (f=0x91c600, throwflag=-1754121928) at Python/ceval.c:3707
#9 0x000000000048c861 in PyEval_EvalCodeEx (co=0x2a95655a80, globals=0x935bf0, locals=0x20, args=0x2a97133930, argcount=1, kws=0x6d19e0, kwcount=0, defs=0x2a97133920, defcount=2, closure=0x0)
    at Python/ceval.c:2875
#10 0x000000000048abdd in PyEval_EvalFrameEx (f=0x6d1860, throwflag=-1754095536) at Python/ceval.c:3707
#11 0x000000000048c861 in PyEval_EvalCodeEx (co=0x2a955ed5d0, globals=0x935bf0, locals=0x20, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2875
#12 0x000000000048c9d2 in PyEval_EvalCode (co=0x20, globals=0x935bf0, locals=0x20) at Python/ceval.c:514
#13 0x00000000004af283 in PyRun_FileExFlags (fp=0x65e010, filename=0x7fbfffc60b "/home/erilov01/python/ipython-0.10/ipython.py", start=0, globals=0x681530, locals=0x681530, closeit=1,
    flags=0x7fbfffc0dc) at Python/pythonrun.c:1273
#14 0x00000000004b011f in PyRun_SimpleFileExFlags (fp=0x65e010, filename=0x7fbfffc60b "/home/erilov01/python/ipython-0.10/ipython.py", closeit=1, flags=0x7fbfffc0dc) at Python/pythonrun.c:879
#15 0x0000000000412061 in Py_Main (argc=0, argv=0x0) at Modules/main.c:532
#16 0x00000031e321c3fb in __libc_start_main () from /lib64/tls/libc.so.6
#17 0x000000000041172a in _start ()

(gdb) up
#1 0x0000002a96d58d6a in py_remove_history (self=0x20, args=0x20) at /arm/scratch/camdan01/depot/python/python/2.5.4/rhe4-x86_64/Modules/readline.c:318
318 /arm/scratch/camdan01/depot/python/python/2.5.4/rhe4-x86_64/Modules/readline.c: No such file or directory.
 in /arm/scratch/camdan01/depot/python/python/2.5.4/rhe4-x86_64/Modules/readline.c
(gdb) info locals
entry_number = 16
entry = (HIST_ENTRY *) 0x92aec0

[Erik Lovlie (eriklovlie)]

Ehm, the "script" I am trying to run should be:

for i in range(10): [enter]
    print 42 [enter]

[Fernando Perez (fdo.perez)]

I don't see the problem on my build of Python:

amirbar[IPython]> python2.5 `which ipython`
Python 2.5.4 (r254:67916, Jan 20 2010, 21:44:03)
Type "copyright", "credits" or "license" for more information.

IPython 0.11.alpha1.bzr.r1223 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object'. ?object also works, ?? prints more.

In [1]: for i in range:
   ...: print 43
   ...:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)

/home/fperez/ipython/repo/trunk-lp/IPython/<ipython console> in <module>()

TypeError: 'builtin_function_or_method' object is not iterable

But in any case, this is a Python bug, not an ipython one. The crash is coming from inside Python itself, nothing done by IPython here plays a role (other than having imported readline, which appears in the traceback, but still it's a Python bug).

You may want to report it to Python itself, closing here.