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From: "Martin Storsjö" <martin@martin.st>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [FFmpeg-cvslog] avfilter/video: don't zero allocated buffers if memory poisoning is used
Date: Tue, 13 Aug 2024 10:22:12 +0300 (EEST)
Message-ID: <5bc48c14-7952-ffcb-204e-21d42d1279c@martin.st> (raw)
In-Reply-To: <20240813021302.DA60E412665@natalya.videolan.org>

On Tue, 13 Aug 2024, James Almer wrote:

> ffmpeg | branch: master | James Almer <jamrial@gmail.com> | Sat Aug 10 21:31:16 2024 -0300| [41307ff3e9384c51d646bff7e3dcf0d554098a8f] | committer: James Almer
>
> avfilter/video: don't zero allocated buffers if memory poisoning is used
>
> Same as in avcodec/get_buffer.c
> Should help in debugging use of uninitialized memory.
>
> Signed-off-by: James Almer <jamrial@gmail.com>
>
>> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=41307ff3e9384c51d646bff7e3dcf0d554098a8f
> ---
>
> libavfilter/video.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)

This change broke a bunch of fate tests - in particular fate-vsynth3-rpza 
and most fate-filter-pixfmts-*.

The issue doesn't show up in normal builds of ffmpeg, unless building with 
--enable-memory-poisoning. And in such a build, tools like valgrind 
doesn't detect the issue right away, as the memory poisoning causes the 
buffers to be deterministically initialized to a nonzero value (but the 
fate test produces the wrong output).

// Martin

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       reply	other threads:[~2024-08-13  7:22 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20240813021302.DA60E412665@natalya.videolan.org>
2024-08-13  7:22 ` Martin Storsjö [this message]
2024-08-13 12:28   ` James Almer

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