Crash in iceloop with Streaming Demo, while using Alpine distribution

[nswarnkar]

Hi,
I am using Alpine distribution(inside docker environment). While every stuff works with Ubuntu docker, but with Alpine I am getting crash always.

Following is backtrace.
https://pastebin.com/embed_js/RUPVgySh

I have taken latest janus code dated 26-May-2017.
I have taken glib 2.44 release, libnice being latest.

Here is sample build scripts(inside docker), which I used:

https://pastebin.com/7B5UvT1p

Please suggest or if any more information is needed, please let me know.

[lminiero]

As explained in the guidelines, please DO NOT paste huge bunches of text inline. That's what gist/pastebin are for. It's also written clearly in the text you deleted to write your own...

[nswarnkar]

Done. Thanks for pointing it out....

Please suggest what wrong we are doing in Alpine.

[lminiero]

I'm personally not familiar with Alpine, but I do know somebody in our team was experiencing a similar problem when playing with Alpine and Raspberry Pi. Probably some system-specific issue that's causing the problem only there. We'll try and replicate the issue in the next few days.

[nswarnkar]

Thanks for revert, I will wait.

[nswarnkar]

Hi Iminiero, did you or team got chance to look into this issue? Thanks in advance.

[lminiero]

Somebody's looking into that. Will come back with more details if any are found.

[atoppi]

Hi nswarnkar,
we can replicate the issue on a Alpine Docker with v0.1.13 libnice, both apk package and source compiled.
The core dump seems OK (no invalid pointer and things like this).
I tried removing some CFLAGS on Janus and libnice without success.
This must be further investigated because the issue is clearly related to the specific OS, but unfortunately we're not so familiar with this Linux distro.

[nswarnkar]

Thanks Toppi for the revert.

Alpine using MUSL instead of standard libc, I doubt that may be creating problem.
Also the crash comes when STUN/TURN phase passes successfully, i.e. during setting up ICE.
could it be that software dependencies(libraries) of Janus are not accurately getting satisfied.?
We also tried with GLIB 2.0, assuming MUSL is working ok. But no luck so far.

[atoppi]

I tried with previous versions of Alpine, glib and gcc too, without success.
Looking at the core dump the crash happens here in libnice:
for (i = agent->streams; i; i = i->next)
so the access to agent->streams is causing the issue.
What is strange is that using the debugger (gdb) that value can be safely read and de-referenced.
Maybe something at runtime is making illegal the access to that pointer. I am not an expert in Linux Kernel security features, but it could be possibile that some security enhancements in Alpine may interfere with the current code.

[atoppi]

I have executed the unit tests on libnice 0.1.13. These are the outputs:

• on Ubuntu 16.04 workstation https://pastebin.com/Librgnen
• on Alpine 3.3.3 Docker instance https://pastebin.com/CEueUzHY

As you can see on Ubuntu everything is OK, while on Alpine there are many seg faults. In particular look at the test-send-recv, line 398.

If you are interested in doing the tests by yourself just issue:
make check
in your local libnice repo.

At this point I think the issue is not specific to Janus, but strictly related to libnice.

[lminiero]

Closing as not a Janus issue.