[FFmpeg-devel] lurking bugs in the mmx-related assembler code (?)

u-h8zb at aetey.se u-h8zb at aetey.se
Mon Oct 3 00:16:02 EEST 2016

Hello Carl Eugen,

On Sun, Oct 02, 2016 at 04:01:21PM +0200, Carl Eugen Hoyos wrote:
> > I do not expect that the ffmpeg developers take the trouble
> > to install an extra build environment with a different libc,
> (If I could just understand this sentence: Is it meant as
> an insult? How do you expect the issue to be fixed? By
> looking at the code? Seriously?)

It is unfortunate if you took this as an insult, it was not.

> looking at the code? Seriously?)

Yes, I am serious.

Frankly, your tone looks unpleasant.
It is a friendly information to make you aware. I guess you were not.

To give you an example of successful code auditing, the corresponding
UB-problem in libtheora was properly fixed without anybody at Xiph having
to install musl.

With all respect to your prefered workflow, it is not the only
possible one and in certain situations may be not the most optimal.

> I can confirm that there is an issue with current musl,

This confirmation is certainly valuable per se.

On the other hand, the underlying problem is not the interaction
with musl, but the reliance of the ffmpeg code on certain UBs.

That's why I still believe that auditing the code is more useful than
hunting once again the hard-to-pinpoint symptoms of the already known

For the sake of clarity: I do not mean any part of this message
as an insult. It is great that you care about ffmpeg, so do I.

Best regards,

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