moqrelayserver crash observed while relaying multiple streams

[gmarzot]

I am doing a lot of unfriendly things to the relay as i test w/ python here... abrupt termination of streams perhaps in the mix or overflowed/dropped messages.

gmarzot@typhoon:~/Projects/moq/upstream/moxygen$ git log
commit 1bb188edb01ddd02dd41658c46ea1ff168af7ef3 (HEAD -> main, origin/main, origin/HEAD)
Author: Open Source Bot <generatedunixname499836121@fb.com>
Date:   Sat Mar 15 09:33:05 2025 -0700

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Reading symbols from ./_build/bin/moqrelayserver...
[New LWP 811128]
[New LWP 811125]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `./_build/bin/moqrelayserver -port 4433 -cert ./certs/fullchain.pem -key ./certs'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  (anonymous namespace)::StreamPublisherImpl::writeToStream (this=0x7f51c00bf490, finStream=false)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/MoQSession.cpp:356
356       auto writeRes =
[Current thread is 1 (Thread 0x7f51c5894640 (LWP 811128))]
(gdb) bt
#0  (anonymous namespace)::StreamPublisherImpl::writeToStream (this=0x7f51c00bf490, finStream=false)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/MoQSession.cpp:356
#1  0x000055b468e6a8a5 in (anonymous namespace)::StreamPublisherImpl::objectPayload (
    this=0x7f51c00bf490, payload=..., finStream=false)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/MoQSession.cpp:461
#2  0x000055b468e1ca95 in moxygen::MoQForwarder::SubgroupForwarder::objectPayload(std::unique_ptr<folly::IOBuf, std::default_delete<folly::IOBuf> >, bool)::{lambda(std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&, std::shared_ptr<moxygen::SubgroupConsumer> const&)#1}::operator()(std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&, std::shared_ptr<moxygen::SubgroupConsumer> const&) const (
    __closure=0x7f51c013f5e0,
    sub=std::shared_ptr<moxygen::MoQForwarder::Subscriber> (use count 2, weak count 0) = {...},
    subgroupConsumer=...)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/relay/MoQForwarder.h:552
#3  0x000055b468e0e91f in std::function<void (std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&)>::operator()(std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&) const (__args#0=...,
    this=0x7f51c588b4d0) at /usr/include/c++/13/bits/std_function.h:591
#4  moxygen::MoQForwarder::forEachSubscriber(std::function<void (std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&)>) (fn=..., this=<optimized out>)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/relay/MoQForwarder.h:221
#5  moxygen::MoQForwarder::SubgroupForwarder::forEachSubscriberSubgroup(std::function<void (std::shared_ptr<moxygen::MoQForwarder::Subscriber> const&, std::shared_ptr<moxygen::SubgroupConsumer> const&)>) (
    fn=..., this=0x7f51c00b8c80)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/relay/MoQForwarder.h:354
#6  moxygen::MoQForwarder::SubgroupForwarder::objectPayload (this=0x7f51c00b8c80, payload=...,
    finSubgroup=<optimized out>)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/relay/MoQForwarder.h:549
#7  0x000055b468e76dbd in moxygen::(anonymous namespace)::ObjectStreamCallback::invokeCallbackNoGroup<folly::Expected<moxygen::ObjectPublishStatus, moxygen::MoQPublishError> (moxygen::SubgroupConsumer::*)(std::unique_ptr<folly::IOBuf>, bool), folly::Expected<moxygen::ObjectPublishStatus, moxygen::MoQPublishError> (moxygen::FetchConsumer::*)(std::unique_ptr<folly::IOBuf>, bool), std::unique_ptr<folly::IOBuf, std::default_delete<folly::IOBuf> >, bool> (
    fmethod=&virtual moxygen::FetchConsumer::objectPayload(std::unique_ptr<folly::IOBuf, std::default_delete<folly::IOBuf> >, bool),
    smethod=&virtual moxygen::SubgroupConsumer::objectPayload(std::unique_ptr<folly::IOBuf, std::default_delete<folly::IOBuf> >, bool), this=0x7f51c00b3de0) at /usr/include/c++/13/bits/unique_ptr.h:197
#8  moxygen::(anonymous namespace)::ObjectStreamCallback::onObjectPayload (this=0x7f51c00b3de0,
    payload=..., objectComplete=<optimized out>)
    at /home/gmarzot/Projects/moq/upstream/moxygen/moxygen/MoQSession.cpp:1588
#9  0x000055b468e51e02 in moxygen::MoQObjectStreamCodec::onIngress (this=<optimized out>, data=...,
    endOfStream=<optimized out>) at /usr/include/c++/13/bits/unique_ptr.h:197
#10 0x000055b468e75db5 in moxygen::MoQSession::unidirectionalReadLoop(_ZN7moxygen10MoQSession22unidirectionalReadLoopESt10shared_ptrIS0_EPN8proxygen12WebTransport16StreamReadHandleE.Frame *) (
    frame_ptr=0x7f51c00b3c30) at /usr/include/c++/13/bits/unique_ptr.h:197
#11 0x000055b468debe92 in std::__n4861::coroutine_handle<void>::resume (this=<synthetic pointer>)
    at /usr/include/c++/11/coroutine:126
#12 folly::resumeCoroutineWithNewAsyncStackRoot (h=..., frame=...)
    at /home/gmarzot/Projects/moq/upstream/moxygen/_build/deps/folly/folly/tracing/AsyncStack.cpp:201
#13 0x000055b468e0718c in folly::coro::detail::ViaCoroutinePromiseBase::executeContinuation (
    this=0x7f51c00c20a0)
    at /home/gmarzot/Projects/moq/upstream/moxygen/_build/deps/include/folly/coro/Coroutine.h:339
#14 folly::coro::detail::ViaCoroutinePromiseBase::scheduleContinuation()::{lambda()#1}::operator()() const (__closure=<optimized out>)
    at /home/gmarzot/Projects/moq/upstream/moxygen/_build/deps/include/folly/coro/ViaIfAsync.h:86
#15 folly::detail::function::call_<folly::coro::detail::ViaCoroutinePromiseBase::scheduleContinuation():```

[afrind]

Is it possible this is #39 ? If so, it should be fixed in main.

[gmarzot]

It's possible. I have not moved forward in a while. But when I do, will watch for this.