[FFmpeg-devel] [PATCH] ffserver: fix memory leaks pointed out by valgrind.

Zalewa PL zalewapl at gmail.com
Sat Apr 15 10:47:58 EEST 2017


> The plan is that if ffserver is not fixed before the next bump, it will
> be removed.

ffserver has been serving our purpose in a 24/7 fashion for about 7 
years now. It will probably be serving us for the foreseeable future, 
whatever the community decides. I prefer to share any fix I make back 
with the community because allowing everyone to build on top of better 
software pays off. If the community drops the program, we most likely 
won't, even if it means being stuck with a single version for years to 
come. However, we still need to get it as stable as possible.

I also admit that I'm not versed in the codebase and whatever change I 
made was based purely on valgrind's output. I understand that my patch 
in its current state is not ideal and I probably should have attempted a 
cleaner fix before submitting. I'll try to do that.

Having stated this, let's get back to the technical topic:

> This accesses plenty of internal fields. (Maybe did so before, but no
> matter.)
> So doing the freeing correctly (if even possible) would be better for
> the survival of ffserver.

At first I was hoping that avformat_free_context() will do the job 
nicely for me, but unfortunately there are some shared objects that get 
destroyed in this call and ffserver eventually crashes. If you run such 
ffserver build in valgrind, it will warn about "free'd memory" accesses.

The problem seems to stem from the "COPY" done in unlayer_stream(). I 
will try to reverse this "COPY" before avformat_free_context() and see 
if it helps.

Best regards,

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