Bug#870622: ffmpeg: autopkgtest SIGBUS on armhf with binutils 2.29

[Matthias Klose]

On 04.08.2017 07:39, Jiong Wang wrote:
> Hi,
> 
>   This issue is caused by a recent change in ARM assembler included since
> Binutils 2.29.
> 
>   The details of that change can be found at
> https://sourceware.org/bugzilla/show_bug.cgi?id=21458
> 
>   The semantics of ADR has changed.  In general, the address generated by ADR
> will guarantee the LSB be set if it's a thumb function address.
> 
>    I noticed h264idct_neon.S is using something like:
> 
> adreq lr,X(ff_h264_idct_add_neon) +CONFIG_THUMB
> 
>    As ADR now will set the LSB automatically, you don't need CONFIG_THUMB any more.
> 
>    I think h264idct_neon.S needs to be updated, and the modification should make
> sure it works with both old Binutils and the new one.

thanks for looking into that.  Also noted that the Debian armhf architecture
cannot assume neon, so maybe we should disable the use of neon in ffmpeg on armhf?

Matthias