Bug#786438: libmp3lame0: general protection error in libmp3lame.so.0.0.0

[Fabian Greffrath]

Hi again,

Am Samstag, den 30.05.2015, 05:12 +0200 schrieb Bernhard Übelacker: 
>  => 0xb76df6c9 <init_xrpow_core_sse+105>:        movaps %xmm0,0x20(%esp)
> 
> Yes, this "movaps" seems to be a SSE instruction.
> Also the changes in the previous patch "should" not change the instructions
> but only the alignment of the memory the instructions operate on.
> And if that is the case, with proper alignment it is working.
> But probably there is a better way to convince gcc to align the memory ...

so, we have a suspect here, but not really a culprit yet.

The main difference between the packages in wheezy and jessie is that
the former is not built with SSE instructions at all. So, it seems that
we have not intriduced a bug, but merely uncovered a bug that was well
hidden before, because the code path in question was never enabled.

The problem is that I am rather illiterate with regard to SSE code, to
me the code looks "all fine". I am thus inclined to disable SSE
instructions again in the lame package. This may be ugly but serves as a
work-around in unstable. But I don't think that such drastic measure is
the most reasonable thing to do to the package in stable.

So, I'd really appreciate if someone with more insight into SSE code
could have a deeper look at it and try to figure out why the code fails
on jessie i386.

- Fabian

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: This is a digitally signed message part
URL: <http://lists.alioth.debian.org/pipermail/pkg-multimedia-maintainers/attachments/20150601/9663fafc/attachment.sig>