[0.x] Possible memory leaks found with libasan latest about janus-gateway

[lminiero]

@arpu please stop linking to the code of third party plugins. As already discussed, we won't inspect or debug code that doesn't belong to this repo.

[vincentfretin]

Thank you @atoppi for your notes, much appreciated.
I'm happy to say we don't have memory leaks anymore in the rust sfu plugin networked-aframe/janus-plugin-sfu#11 with loop_events option specified and the following versions

• ubuntu 24.04
• libwebsockets 4.3.3
• libstrp 2.6.0
• usrsctp master c4b52c34d4a7ecca6c992ba2f7f09607997d8ead
• libnice 48dac0d702b134f7b11b92602c234ba1120cc75b (post 0.1.18)

with the two following fixes:

• #3371
• #3374

But we have the following direct leak with latest libnice:

Direct leak of 69840 byte(s) in 2 object(s) allocated from:
    #0 0x725d9ca7e4d0 in calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:77
    #1 0x725d9c5ec7a1 in g_malloc0 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x637a1) (BuildId: 9753724b85d60f97b5d5663181ef7f4e69a62131)
    #2 0x580861beb9a4 in janus_sctp_association_create /janus-gateway/sctp.c:189
    #3 0x580861ad1e47 in janus_dtls_srtp_create_sctp /janus-gateway/dtls.c:689
    #4 0x580861b748e6 in janus_process_incoming_request /janus-gateway/janus.c:1662
    #5 0x580861b84b37 in janus_transport_task /janus-gateway/janus.c:3478
    #6 0x725d9c61a541  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x91541) (BuildId: 9753724b85d60f97b5d5663181ef7f4e69a62131)
    #7 0x725d9c614c81  (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x8bc81) (BuildId: 9753724b85d60f97b5d5663181ef7f4e69a62131)
    #8 0x725d9c9e1109 in asan_thread_start ../../../../src/libsanitizer/asan/asan_interceptors.cpp:234

g_malloc0 is from (in 0.x branch)

janus-gateway/sctp.c

Line 189 in a7767ad

janus_sctp_association *sctp = g_malloc0(sizeof(janus_sctp_association));

As far as I can see this has nothing to do with the rust plugin and janus_sctp_association_destroy(sctp) seems to be called in all relevant cases. So I really have no clue about this one.

I tested the following libnice versions:
ok libnice 2020-07-06 13:53 (post 0.1.18) 48dac0d702b134f7b11b92602c234ba1120cc75b agent: keep a track of the candidate refreshes being pruned
ok libnice 2020-12-06 19:09 (post 0.1.18) b353f30cfce498ffc2f1057d2d14aeb4b183e671 udp-turn: don't allocate large arrays on the stack
ko libnice 2020-12-06 19:12 (post 0.1.18) a3f535669de74ba707fbd11c268ac04e60564a65 agent: don't allocate large arrays on the stack
=> the two previous commits come from https://gitlab.freedesktop.org/libnice/libnice/-/merge_requests/171
ko libnice 2021-04-20 15:09 (post 0.1.18) 8ccac4b04759edaecead7470e28865aff8066921
...
ko libnice 2024-03-04 (0.1.22) ae3eb16fd7d1237353bf64e899c612b8a63bca8a

I know you guys don't support debugging third party plugin. I'm just putting this here in case it rings a bell to you and there is something obvious for you or maybe an incompatibility between libstrp and libnice versions you know of.

[arpu]

Versions:
LIBNICE="0.1.22"
SRTP="2.6.0"
usrsctp latest c4b52c34d4a7ecca6c992ba2f7f09607997d8ead

loop_index is set to 4

build on Ubuntu 24.04 in Docker

jnaus build with:
CFLAGS="${CFLAGS} -O0 -g -ggdb3 -fno-omit-frame-pointer -fsanitize=address -fno-sanitize-recover=all -fsanitize-address-use-after-scope" LDFLAGS="-fsanitize=address" ./configure --prefix=/usr --disable-all-plugins --disable-all-handlers

[lminiero]

I'm sorry, but I won't debug logs related to plugins that are not part of this repo, let alone potentially proprietary ones. If you can replicate the problem with the stock code feel free to reopen.

[atoppi]

a few notes:

• Having memory growing with libasan is expected and a known thing
• Before hitting CTRL-C you need to destroy the sessions or you might have "false positives" due to the multi threaded nature of the server. Only leaks detected AFTER session cleanup are true leaks
• I made a quick test with 3 participants (audio + video + data) and had no leak. We detected a FPE though and we fixed it backporting a patch from 1.x
• I noticed your scenario involves renegotiations. I did not test them, but if you want to try replicating with VR sfu I guess this is something to consider

[arpu]

understand and thanks for the Feedback

@atoppi i add a new test and the session is closed after i hit CTRL-C

the new test was with older ubuntu 20.04 LTS and not enable event_loop
https://gist.github.com/arpu/8fa1751b9473534f85e9d755d5c90946

[arpu]

@atoppi can i ask what version of https://github.com/sctplab/usrsctp is used in your test?
because i see #2 0x555e8987d127 in janus_dtls_srtp_create_sctp /janus-gateway/dtls.c:689

i wonder if this has something to do with the datachannels

[atoppi]

commit c4b52c34d4a7ecca6c992ba2f7f09607997d8ead from April '24.
This issue is very likely caused by the rust plugin not releasing resources.

[arpu]

Thank you, used the same version on test

do you have any Idea what resources, we should look at in the rust plugin?
https://github.com/networked-aframe/janus-plugin-sfu/blob/master/src/lib.rs#L325

[arpu]

any interests to bring this rust plugin to the official janus repo?

[arpu]

Question if we send a Datachannel with the plugin as message a DataChannel is opened https://github.com/meetecho/janus-gateway/blob/0.x/janus.c#L1662

do we need to use janus_dtls_srtp_destroy and free in the Plugin?

[arpu]

this is the cleanup after removing 2 clients from same room ( audio video datachannel)
https://gist.github.com/arpu/e7687ce4e1da38c0a6d21366e11c61ea