[FFmpeg-devel] [RFC] d3dva security hw+threads

[Soft Works]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Anton Khirnov
> Sent: Sunday, September 4, 2022 8:58 AM
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [RFC] d3dva security hw+threads
> 
> Quoting Timo Rothenpieler (2022-09-02 01:46:59)
> > On 02.09.2022 01:32, Michael Niedermayer wrote:
> > > Hi all
> > >
> > > Theres a use after free issue in H.264 Decoding on d3d11va with
> multiple threads
> > > I dont have the hardware/platform nor do i know the hw decoding
> code so i made
> > > no attempt to fix this beyond asking others to ...
> >
> > hwaccel with multiple threads being broken is not exactly a
> surprise.
> > So we could just disable that, and always have it be one single
> thread?
> 
> We are already disabling it in a way - the frame threading code
> ensures
> that threads run one at a time when hwaccel is being used.


Is there a described way to repro? I would try whether it still 
happens after removing the lock code in hwcontext_d3d11va.c.
Those locks are not really needed and might prevent release 
of dx11 resources in proper order. It's a guess only but 
easy to try.

softworkz