Testcase found while fuzzing mozilla-central rev 1cb2015e6fbc (built with: --enable-debug --enable-fuzzing).

Testcase can be reproduced using the following commands:

$ pip install fuzzfetch grizzly-framework
$ python -m fuzzfetch --build 1cb2015e6fbc --debug --fuzzing -n firefox
$ python -m grizzly.replay ./firefox/firefox testcase.html

Assertion failure: aGraph->GraphRate() == ctx->SampleRate(), at /dom/media/webaudio/AudioNodeExternalInputTrack.cpp:33

    ==76589==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f377dcf2eea bp 0x7ffc385b84f0 sp 0x7ffc385b84c0 T76589)
    ==76589==The signal is caused by a WRITE memory access.
    ==76589==Hint: address points to the zero page.
        #0 0x7f377dcf2eea in mozilla::AudioNodeExternalInputTrack::Create(mozilla::MediaTrackGraph*, mozilla::AudioNodeEngine*) /dom/media/webaudio/AudioNodeExternalInputTrack.cpp:33:3
        #1 0x7f377dd2890c in mozilla::dom::MediaStreamAudioSourceNode::Init(mozilla::DOMMediaStream&, mozilla::ErrorResult&) /dom/media/webaudio/MediaStreamAudioSourceNode.cpp:69:12
        #2 0x7f377dd286f1 in mozilla::dom::MediaElementAudioSourceNode::Create(mozilla::dom::AudioContext&, mozilla::dom::MediaElementAudioSourceOptions const&, mozilla::ErrorResult&) /dom/media/webaudio/MediaElementAudioSourceNode.cpp:61:9
        #3 0x7f377dce4e12 in mozilla::dom::AudioContext::CreateMediaElementSource(mozilla::dom::HTMLMediaElement&, mozilla::ErrorResult&) /dom/media/webaudio/AudioContext.cpp:448:10
        #4 0x7f377bdc343e in mozilla::dom::AudioContext_Binding::createMediaElementSource(JSContext*, JS::Handle<JSObject*>, void*, JSJitMethodCallArgs const&) /builds/worker/workspace/obj-build/dom/bindings/AudioContextBinding.cpp:492:94
        #5 0x7f377cfbd3f8 in bool mozilla::dom::binding_detail::GenericMethod<mozilla::dom::binding_detail::NormalThisPolicy, mozilla::dom::binding_detail::ThrowExceptions>(JSContext*, unsigned int, JS::Value*) /dom/bindings/BindingUtils.cpp:3306:13
        #6 0x7f3780a167af in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /js/src/vm/Interpreter.cpp:425:13
        #7 0x7f3780a15ead in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /js/src/vm/Interpreter.cpp:512:12
        #8 0x7f3780a1798e in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /js/src/vm/Interpreter.cpp:572:10
        #9 0x7f3780a0d196 in CallFromStack /js/src/vm/Interpreter.cpp:576:10
        #10 0x7f3780a0d196 in Interpret(JSContext*, js::RunState&) /js/src/vm/Interpreter.cpp:3309:16
        #11 0x7f3780a040b3 in js::RunScript(JSContext*, js::RunState&) /js/src/vm/Interpreter.cpp:394:13
        #12 0x7f3780a15da8 in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /js/src/vm/Interpreter.cpp:544:13
        #13 0x7f3780a1798e in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /js/src/vm/Interpreter.cpp:572:10
        #14 0x7f3780a17b91 in js::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, js::AnyInvokeArgs const&, JS::MutableHandle<JS::Value>, js::CallReason) /js/src/vm/Interpreter.cpp:589:8
        #15 0x7f3780bd6fa1 in JS::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, JS::HandleValueArray const&, JS::MutableHandle<JS::Value>) /js/src/vm/CallAndConstruct.cpp:117:10
        #16 0x7f377cd5af54 in mozilla::dom::Function::Call(mozilla::dom::BindingCallContext&, JS::Handle<JS::Value>, nsTArray<JS::Value> const&, JS::MutableHandle<JS::Value>, mozilla::ErrorResult&) /builds/worker/workspace/obj-build/dom/bindings/FunctionBinding.cpp:50:8
        #17 0x7f377bbd9382 in void mozilla::dom::Function::Call<nsCOMPtr<nsIGlobalObject> >(nsCOMPtr<nsIGlobalObject> const&, nsTArray<JS::Value> const&, JS::MutableHandle<JS::Value>, mozilla::ErrorResult&, char const*, mozilla::dom::CallbackObject::ExceptionHandling, JS::Realm*) /builds/worker/workspace/obj-build/dist/include/mozilla/dom/FunctionBinding.h:71:12
        #18 0x7f377bbd911d in mozilla::dom::CallbackTimeoutHandler::Call(char const*) /dom/base/TimeoutHandler.cpp:167:29
        #19 0x7f377b8befa1 in nsGlobalWindowInner::RunTimeoutHandler(mozilla::dom::Timeout*, nsIScriptContext*) /dom/base/nsGlobalWindowInner.cpp:6291:38
        #20 0x7f377bbd5da3 in mozilla::dom::TimeoutManager::RunTimeout(mozilla::TimeStamp const&, mozilla::TimeStamp const&, bool) /dom/base/TimeoutManager.cpp:893:44
        #21 0x7f377bbd4e00 in mozilla::dom::TimeoutExecutor::MaybeExecute() /dom/base/TimeoutExecutor.cpp:179:11
        #22 0x7f377bbd7209 in Notify /dom/base/TimeoutExecutor.cpp:246:5
        #23 0x7f377bbd7209 in non-virtual thunk to mozilla::dom::TimeoutExecutor::Notify(nsITimer*) /dom/base/TimeoutExecutor.cpp
        #24 0x7f3779c5391d in operator() /xpcom/threads/nsTimerImpl.cpp:654:44
        #25 0x7f3779c5391d in matchN<mozilla::Variant<nsTimerImpl::UnknownCallback, nsCOMPtr<nsITimerCallback>, nsCOMPtr<nsIObserver>, nsTimerImpl::FuncCallback, nsTimerImpl::ClosureCallback> &, (lambda at /xpcom/threads/nsTimerImpl.cpp:654:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:655:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:658:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:659:7)> /builds/worker/workspace/obj-build/dist/include/mozilla/Variant.h:309:16
        #26 0x7f3779c5391d in matchN<mozilla::Variant<nsTimerImpl::UnknownCallback, nsCOMPtr<nsITimerCallback>, nsCOMPtr<nsIObserver>, nsTimerImpl::FuncCallback, nsTimerImpl::ClosureCallback> &, (lambda at /xpcom/threads/nsTimerImpl.cpp:653:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:654:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:655:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:658:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:659:7)> /builds/worker/workspace/obj-build/dist/include/mozilla/Variant.h:318:14
        #27 0x7f3779c5391d in matchN<mozilla::Variant<nsTimerImpl::UnknownCallback, nsCOMPtr<nsITimerCallback>, nsCOMPtr<nsIObserver>, nsTimerImpl::FuncCallback, nsTimerImpl::ClosureCallback> &, (lambda at /xpcom/threads/nsTimerImpl.cpp:653:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:654:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:655:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:658:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:659:7)> /builds/worker/workspace/obj-build/dist/include/mozilla/Variant.h:902:12
        #28 0x7f3779c5391d in match<(lambda at /xpcom/threads/nsTimerImpl.cpp:653:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:654:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:655:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:658:7), (lambda at /xpcom/threads/nsTimerImpl.cpp:659:7)> /builds/worker/workspace/obj-build/dist/include/mozilla/Variant.h:857:12
        #29 0x7f3779c5391d in nsTimerImpl::Fire(int) /xpcom/threads/nsTimerImpl.cpp:652:22
        #30 0x7f3779c2556e in nsTimerEvent::Run() /xpcom/threads/TimerThread.cpp:265:11
        #31 0x7f3779c446ea in mozilla::ThrottledEventQueue::Inner::ExecuteRunnable() /xpcom/threads/ThrottledEventQueue.cpp:254:22
        #32 0x7f3779c41951 in mozilla::ThrottledEventQueue::Inner::Executor::Run() /xpcom/threads/ThrottledEventQueue.cpp:81:15
        #33 0x7f3779c42a7e in mozilla::RunnableTask::Run() /xpcom/threads/TaskController.cpp:468:16
        #34 0x7f3779c1c716 in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:771:26
        #35 0x7f3779c1b3d8 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /xpcom/threads/TaskController.cpp:607:15
        #36 0x7f3779c1b653 in mozilla::TaskController::ProcessPendingMTTask(bool) /xpcom/threads/TaskController.cpp:391:36
        #37 0x7f3779c46159 in operator() /xpcom/threads/TaskController.cpp:127:37
        #38 0x7f3779c46159 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_1>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:531:5
        #39 0x7f3779c31053 in nsThread::ProcessNextEvent(bool, bool*) /xpcom/threads/nsThread.cpp:1183:16
        #40 0x7f3779c382ba in NS_ProcessNextEvent(nsIThread*, bool) /xpcom/threads/nsThreadUtils.cpp:467:10
        #41 0x7f377a6dab84 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:107:5
        #42 0x7f377a5fa0b7 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #43 0x7f377a5f9fc2 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #44 0x7f377a5f9fc2 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #45 0x7f377e8775a8 in nsBaseAppShell::Run() /widget/nsBaseAppShell.cpp:137:27
        #46 0x7f378089a333 in XRE_RunAppShell() /toolkit/xre/nsEmbedFunctions.cpp:864:20
        #47 0x7f377a6dbaca in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /ipc/glue/MessagePump.cpp:235:9
        #48 0x7f377a5fa0b7 in MessageLoop::RunInternal() /ipc/chromium/src/base/message_loop.cc:331:10
        #49 0x7f377a5f9fc2 in RunHandler /ipc/chromium/src/base/message_loop.cc:324:3
        #50 0x7f377a5f9fc2 in MessageLoop::Run() /ipc/chromium/src/base/message_loop.cc:306:3
        #51 0x7f378089996b in XRE_InitChildProcess(int, char**, XREChildData const*) /toolkit/xre/nsEmbedFunctions.cpp:701:34
        #52 0x56305066f029 in content_process_main /browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
        #53 0x56305066f029 in main /browser/app/nsBrowserApp.cpp:327:18
        #54 0x7f378eeda0b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
        #55 0x56305064a7bc in _start (/home/jkratzer/builds/mc-debug/firefox-bin+0x157bc)
    
    UndefinedBehaviorSanitizer can not provide additional info.
    SUMMARY: UndefinedBehaviorSanitizer: SEGV /dom/media/webaudio/AudioNodeExternalInputTrack.cpp:33:3 in mozilla::AudioNodeExternalInputTrack::Create(mozilla::MediaTrackGraph*, mozilla::AudioNodeEngine*)
    ==76589==ABORTING

Bugmon Analysis
Verified bug as reproducible on mozilla-central 20220103215519-a6af5cff5adf.
Failed to bisect testcase (Testcase reproduces on start build!):

Start: 1d89f3cb5bb3e5a37b0249977838c4a98c162c80 (20210105043131)
End: 1cb2015e6fbc11f3a03137692fe60b111b94693a (20220103092929)
BuildFlags: BuildFlags(asan=False, tsan=False, debug=True, fuzzing=True, coverage=False, valgrind=False, no_opt=False, fuzzilli=False)

What is happening here is that the left hand side operand of the equality
operator is an integer, and the right hand side operand is a float, that has a
fractional value that is not null. The left hand side gets promoted to a float
and the equality check fails.

In practice, the graph is always instantiated with a sample-rate that is an
integer, and this conversion happens without explicit rounding, so it's a floor
operation. However, the sample-rate of an AudioContext is a float, so there is
an edge case where the graph and the AudioContext don't have the same
sample-rate.

I don't think this matters in practice.

Switching to comparing that the graph passed as a parameter is the same as the
graph the AudioNode is in is enough to assert here and doesn't suffer from the
sample-rate problem.

https://hg.mozilla.org/mozilla-central/rev/ace01ed41aca

Bugmon Analysis
Verified bug as fixed on rev mozilla-central 20220105170324-138105a14659.
Removing bugmon keyword as no further action possible. Please review the bug and re-add the keyword for further analysis.

:padenot, since this bug contains a bisection range, could you fill (if possible) the regressed_by field?
For more information, please visit auto_nag documentation.

Sorry, bug in the bot.