[Python-Dev] Invalid memory read in PyObject_Free

Michael Hudson mwh@python.net
Fri, 04 Jul 2003 17:38:36 +0100

Guido van Rossum <guido@python.org> writes:

>> In obmalloc.c there is some code that does not strictly conform to
>> ANSI C.
> True.  If we wanted to strictly conform to ANSI C, we couldn't do many
> things we do.

Sure, but this one is a little bit more eccentric than the others...

>> However, I do not believe there have been reports of machines
>> in the wild where this is a problem, and on such platforms there is an
>> easy solution: turn off pymalloc.
> I think there is talk though to make it impossible to turn off
> pymalloc in the future (you can still turn it off in Python 2.3).
> I haven't heard of platforms where turning off pymalloc is required --
> unless we hear about those, I expect that for 2.4, pymalloc may no
> longer be optional.  (The reason: maintaining two versions of the same
> code is a pain, and usually the version that's not selected by default
> is severely broken after a few releases.)

Is this a real problem with pymalloc?

#ifndef PYMALLOC
#define PyObject_Alloc malloc

isn't likely to bitrot that fast.  But, whatever, it's no big deal to


  People think I'm a nice guy, and the fact is that I'm a scheming,
  conniving bastard who doesn't care for any hurt feelings or lost
  hours of work if it just results in what I consider to be a better
  system.                                            -- Linus Torvalds