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From: Sean McGovern <gseanmcg@gmail.com>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] FATE vc1-* failures on PowerPC64 with GCC Address Sanitizer
Date: Thu, 30 Jan 2025 23:57:32 -0500
Message-ID: <CAPBf_O=Efhopa7AP4hCavec=OFRFBw-Ac5tDn33HR+CMGf25_g@mail.gmail.com> (raw)

Hi,

I recently added a new FATE node 'ppc64-linux-gcc-14.2-asan' that runs
GCC Address Sanitizer on my G5 PowerMac.

It currently shows test failures for the vc1-* tests and wmv3-drm-dec
due to the AltiVec acceleration in libavcodec/ppc/vc1dsp_altivec.c
over-reading if the final block is less than 128 bytes[1].

I'm not sure how to go about fixing that -- would it be safe to just
bump the allocated DSP context block to align to that (using
av_cpu_max_align() like magicyuvenc does?) on [2] ?

My other thought was much more drastic -- should we be processing the
final block using the scalar version of the DSP code if it does not
align?

Comments/suggestions are appreciated,
Sean McGovern

[1] https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/ppc/vc1dsp_altivec.c;h=bbadb2aaeef098449e48d8f6f47c2fc2d9809b8d;hb=HEAD#l252
[2] https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/vc1dec.c;h=2c314e7b55b9ab7983f565b2ac2bbb08ef0770c6;hb=HEAD#l377
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                 reply	other threads:[~2025-01-31  4:57 UTC|newest]

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