[Python-Dev] Can someone try to duplicate corruption on Gentoo?

[R. David Murray]

On Thu, 29 Aug 2013 18:43:13 -0500, Tim Peters <tim.peters at gmail.com> wrote:
> In
> 
>     http://bugs.python.org/issue18843
> 
> a user reported a debug PyMalloc "bad leading pad byte" memory
> corruption death while running their code.  After some thrashing, they
> decided to rebuild Python, and got the same kind of error while
> rebuilding Python.  See
> 
>     http://bugs.python.org/msg196481
> 
> in that bug report:
> 
> """
> # emerge dev-lang/python:2.7
> 
>  * IMPORTANT: 11 news items need reading for repository 'gentoo'.
>  * Use eselect news to read news items.
> 
> Calculating dependencies... done!
> Debug memory block at address p=0xa7f5900: API 'o'
>     80 bytes originally requested
>     The 7 pad bytes at p-7 are not all FORBIDDENBYTE (0xfb):
>         at p-7: 0xfb
>         at p-6: 0xfb
>         at p-5: 0xfa *** OUCH
>         at p-4: 0xfb
>         at p-3: 0xfb
>         at p-2: 0xfb
>         at p-1: 0xfb
>     Because memory is corrupted at the start, the count of bytes requested
>        may be bogus, and checking the trailing pad bytes may segfault.
>     The 8 pad bytes at tail=0xa7f5950 are FORBIDDENBYTE, as expected.
>     The block was made by call #21242094 to debug malloc/realloc.
>     Data at p: 73 00 00 00 79 00 00 00 ... 67 00 00 00 00 00 00 00
> Fatal Python error: bad leading pad byte
> Aborted (core dumped)

Emerge uses Python, and 2.7 is the default system python on Gentoo,
so unless he changed his default, that error almost certainly came from
the existing Python he was having trouble with.

Just for fun I re-emerged 2.7.3-r3 on my system, and that worked fine.

--David