On Wed, May 03, 2017 at 03:28:53PM +0200, Hendrik Leppkes wrote: > On Wed, May 3, 2017 at 3:23 PM, Michael Niedermayer > <mich...@niedermayer.cc> wrote: > > On Wed, May 03, 2017 at 12:54:53PM +0200, Hendrik Leppkes wrote: > >> On Wed, May 3, 2017 at 11:50 AM, Michael Niedermayer > >> <mich...@niedermayer.cc> wrote: > >> > On Wed, May 03, 2017 at 11:37:35AM +0200, wm4 wrote: > >> >> On Wed, 3 May 2017 11:29:04 +0200 > >> >> Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> >> > >> >> > On Wed, May 03, 2017 at 05:29:07AM +0200, wm4 wrote: > >> >> > > On Wed, 3 May 2017 05:21:50 +0200 > >> >> > > Michael Niedermayer <mich...@niedermayer.cc> wrote: > >> >> > > > >> >> > > > Fixes timeout > >> >> > > > Fixes: 1293/clusterfuzz-testcase-minimized-6054752074858496 > >> >> > > > > >> >> > > > Found-by: continuous fuzzing process > >> >> > > > https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg > >> >> > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > >> >> > > > --- > >> >> > > > libavcodec/avpacket.c | 3 +++ > >> >> > > > 1 file changed, 3 insertions(+) > >> >> > > > > >> >> > > > diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c > >> >> > > > index 4bf830bb8a..ff7ee730a4 100644 > >> >> > > > --- a/libavcodec/avpacket.c > >> >> > > > +++ b/libavcodec/avpacket.c > >> >> > > > @@ -557,6 +557,9 @@ FF_ENABLE_DEPRECATION_WARNINGS > >> >> > > > dst->flags = src->flags; > >> >> > > > dst->stream_index = src->stream_index; > >> >> > > > > >> >> > > > + if (!dst->side_data_elems); > >> >> > > > + return av_copy_packet_side_data(dst, src); > >> >> > > > + > >> >> > > > for (i = 0; i < src->side_data_elems; i++) { > >> >> > > > enum AVPacketSideDataType type = src->side_data[i].type; > >> >> > > > int size = src->side_data[i].size; > >> >> > > > >> >> > > This doesn't look right... > >> >> > > >> >> > already fixed the ; locally > >> >> > > >> >> > > >> >> > [...] > >> >> > >> >> I didn't see that, I was referring to the fact that you call > >> >> av_copy_packet_side_data(), and only sometimes (at least by intention). > >> >> That requires at least an explanation in the commit message. > >> > > >> > av_packet_copy_props() would add side data to the destination packet > >> > it doesnt replace previously existing side data except in case of > >> > error. > >> > I dont know if that is intended but i didnt want to change it as that > >> > would be unrelated to this patch > >> > > >> > >> This behavior seems odd at best, so maybe we should just change that > >> and make the behavior more logical, and fix your issue at the same > >> time? > > > > That can be done and makes alot of sense after the patch. > > > > we need to fix this issue in our releases too > > a simple bugfix and a seperate behavior change afterwards allows us > > to simply backport the bugfix from master. > > > > If anything your "bugfix" here is a performance improvement, and I > don't think that warrants backporting either way.
Before the patch the sample file takes 51seconds to decode, after it, it takes 203 milliseconds. The difference is caused by only 2 calls to the copy code blocking a machine for 51 seconds for something that decodes in 203ms otherwise, is IMO worth backporting a fix for. We can add a bound to the number of side data elements if theres consens about doing that and doing it in releases. still, no code should call realloc() in a loop when it can do one (re)allocation call at the top. [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Into a blind darkness they enter who follow after the Ignorance, they as if into a greater darkness enter who devote themselves to the Knowledge alone. -- Isha Upanishad
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