[FFmpeg-devel] [PATCH 1/2] avformat/mov: zero initialize codec_name in mov_parse_stsd_video()

Michael Niedermayer michael at niedermayer.cc
Thu Oct 20 04:25:21 EEST 2016


On Wed, Oct 19, 2016 at 07:30:29PM +0200, Andreas Cadhalpun wrote:
> On 19.10.2016 04:15, James Almer wrote:
> > On 10/17/2016 9:57 PM, Michael Niedermayer wrote:
> >> On Sun, Oct 16, 2016 at 09:34:50PM -0300, James Almer wrote:
> >>> Fixes valgrind warning about "Conditional jump or move depends on uninitialised value(s)"
> >>>
> >>> Signed-off-by: James Almer <jamrial at gmail.com>
> >>> ---
> >>>  libavformat/mov.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> This should be suppressable by adding it to
> >> tests/fate-valgrind.supp
> > 
> > I'll leave that to someone else. No idea how to add stuff to that file.
> > 
> > Should i drop this patch? Zero initializing a buffer in stack wouldn't
> > hurt IMO.
> 
> I prefer fixing such things in the code if it's reasonable possible, which
> is the case here. In other words, the patch looks good to me.

I think the bug is that valgrind misinterprets highly optimized libc/gcc
code, i might be wrong though as i didnt disassemble and analyze this,
that was just my feeling ...
But if true a change to ffmpeg can only workaround but not fix this


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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