https://treeherder.mozilla.org/logviewer?job_id=335524965&repo=try&lineNumber=3979

Write of size 8 at 0x7b5400013c90 by main thread (mutexes: write M248115055189638024):
[task 2021-04-06T09:13:04.986Z] 09:13:04     INFO -  PID 19690 |     #0 assign_assuming_AddRef /builds/worker/workspace/obj-build/dist/include/mozilla/RefPtr.h:67:13 (libxul.so+0xe39c06)
[task 2021-04-06T09:13:04.986Z] 09:13:04     INFO -  PID 19690 |     #1 operator= /builds/worker/workspace/obj-build/dist/include/mozilla/RefPtr.h:168:5 (libxul.so+0xe39c06)
[task 2021-04-06T09:13:04.987Z] 09:13:04     INFO -  PID 19690 |     #2 mozilla::net::TRRService::HandleConfirmationEvent(mozilla::net::TRRService::ConfirmationEvent, mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&)::$_3::operator()() const /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:684:25 (libxul.so+0xe39c06)
[task 2021-04-06T09:13:04.987Z] 09:13:04     INFO -  PID 19690 |     #3 HandleConfirmationEvent /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:780:7 (libxul.so+0xe386bc)
[task 2021-04-06T09:13:04.987Z] 09:13:04     INFO -  PID 19690 |     #4 HandleConfirmationEvent /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:676:3 (libxul.so+0xe386bc)
[task 2021-04-06T09:13:04.987Z] 09:13:04     INFO -  PID 19690 |     #5 mozilla::net::TRRService::Observe(nsISupports*, char const*, char16_t const*) /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:591:5 (libxul.so+0xe386bc)
[task 2021-04-06T09:13:04.988Z] 09:13:04     INFO -  PID 19690 |     #6 non-virtual thunk to mozilla::net::TRRService::Observe(nsISupports*, char const*, char16_t const*) /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp (libxul.so+0xe39ba5)
[task 2021-04-06T09:13:04.989Z] 09:13:04     INFO -  PID 19690 |     #7 nsPrefBranch::NotifyObserver(char const*, void*) /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:2688:13 (libxul.so+0xc2be10)
[task 2021-04-06T09:13:04.989Z] 09:13:04     INFO -  PID 19690 |     #8 NotifyCallbacks(nsTString<char> const&, PrefWrapper const*) /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:1684:9 (libxul.so+0xc4634d)
[task 2021-04-06T09:13:04.990Z] 09:13:04     INFO -  PID 19690 |     #9 NotifyCallbacks /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:1451:3 (libxul.so+0xc7ff42)
[task 2021-04-06T09:13:04.991Z] 09:13:04     INFO -  PID 19690 |     #10 pref_SetPref(nsTString<char> const&, mozilla::PrefType, mozilla::PrefValueKind, PrefValue, bool, bool, bool) /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:1642:5 (libxul.so+0xc7ff42)
[task 2021-04-06T09:13:04.991Z] 09:13:04     INFO -  PID 19690 |     #11 mozilla::Preferences::SetBool(char const*, bool, mozilla::PrefValueKind) /builds/worker/checkouts/gecko/modules/libpref/Preferences.cpp:4883:10 (libxul.so+0xc26ca9)
[task 2021-04-06T09:13:04.992Z] 09:13:04     INFO -  PID 19690 |     #12 RemoveTRRBlocklistFile /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:135:3 (libxul.so+0xe4966d)
[task 2021-04-06T09:13:04.992Z] 09:13:04     INFO -  PID 19690 |     #13 operator() /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:194:49 (libxul.so+0xe4966d)
[task 2021-04-06T09:13:04.992Z] 09:13:04     INFO -  PID 19690 |     #14 already_AddRefed<mozilla::CancelableRunnable> NS_NewCancelableRunnableFunction<mozilla::net::TRRService::Init()::$_0>(char const*, mozilla::net::TRRService::Init()::$_0&&)::FuncCancelableRunnable::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:652:9 (libxul.so+0xe4966d)
[task 2021-04-06T09:13:04.993Z] 09:13:04     INFO -  PID 19690 |     #15 mozilla::RunnableTask::Run() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:470:16 (libxul.so+0xbd5032)
[task 2021-04-06T09:13:04.993Z] 09:13:04     INFO -  PID 19690 |     #16 mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:754:26 (libxul.so+0xbd2f4c)
[task 2021-04-06T09:13:04.993Z] 09:13:04     INFO -  PID 19690 |     #17 mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:632:15 (libxul.so+0xbd19f9)
[task 2021-04-06T09:13:04.994Z] 09:13:04     INFO -  PID 19690 |     #18 mozilla::TaskController::ProcessPendingMTTask(bool) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:393:36 (libxul.so+0xbd1b64)
[task 2021-04-06T09:13:04.995Z] 09:13:04     INFO -  PID 19690 |     #19 operator() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:136:37 (libxul.so+0xbd7eea)
[task 2021-04-06T09:13:04.995Z] 09:13:04     INFO -  PID 19690 |     #20 mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_4>::Run() /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.h:534:5 (libxul.so+0xbd7eea)
[task 2021-04-06T09:13:04.995Z] 09:13:04     INFO -  PID 19690 |     #21 nsThread::ProcessNextEvent(bool, bool*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:1155:16 (libxul.so+0xbe8d26)
[task 2021-04-06T09:13:04.996Z] 09:13:04     INFO -  PID 19690 |     #22 NS_ProcessNextEvent(nsIThread*, bool) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.cpp:548:10 (libxul.so+0xbef312)
[task 2021-04-06T09:13:04.996Z] 09:13:04     INFO -  PID 19690 |     #23 SpinEventLoopUntil<mozilla::ProcessFailureBehavior::ReportToCaller, (lambda at /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:695:36)> /builds/worker/workspace/obj-build/dist/include/mozilla/SpinEventLoopUntil.h:93:25 (libxul.so+0xbeeca2)
[task 2021-04-06T09:13:04.997Z] 09:13:04     INFO -  PID 19690 |     #24 nsThreadManager::SpinEventLoopUntilInternal(nsTSubstring<char> const&, nsINestedEventLoopCondition*, mozilla::ShutdownPhase) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:695:8 (libxul.so+0xbeeca2)
[task 2021-04-06T09:13:04.998Z] 09:13:04     INFO -  PID 19690 |     #25 nsThreadManager::SpinEventLoopUntil(nsTSubstring<char> const&, nsINestedEventLoopCondition*) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:621:10 (libxul.so+0xbee7e3)
[task 2021-04-06T09:13:04.998Z] 09:13:04     INFO -  PID 19690 |     #26 NS_InvokeByIndex /builds/worker/checkouts/gecko/xpcom/reflect/xptcall/md/unix/xptcinvoke_asm_x86_64_unix.S:101 (libxul.so+0xc10875)
[task 2021-04-06T09:13:04.999Z] 09:13:04     INFO -  PID 19690 |     #27 XPC_WN_CallMethod(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/js/xpconnect/src/XPCWrappedNativeJSOps.cpp:925:10 (libxul.so+0x1adc00a)
[task 2021-04-06T09:13:05.002Z] 09:13:05     INFO -  PID 19690 |     #28 CallJSNative /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:435:13 (libxul.so+0x69d340c)
[task 2021-04-06T09:13:05.002Z] 09:13:05     INFO -  PID 19690 |     #29 js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:520:12 (libxul.so+0x69d340c)
[task 2021-04-06T09:13:05.003Z] 09:13:05     INFO -  PID 19690 |     #30 InternalCall /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:580:10 (libxul.so+0x69c8e3b)
[task 2021-04-06T09:13:05.003Z] 09:13:05     INFO -  PID 19690 |     #31 CallFromStack /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:584:10 (libxul.so+0x69c8e3b)
[task 2021-04-06T09:13:05.004Z] 09:13:05     INFO -  PID 19690 |     #32 Interpret(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:3244:16 (libxul.so+0x69c8e3b)
[task 2021-04-06T09:13:05.004Z] 09:13:05     INFO -  PID 19690 |     #33 js::RunScript(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:405:13 (libxul.so+0x69bb8cc)
[task 2021-04-06T09:13:05.005Z] 09:13:05     INFO -  PID 19690 |     #34 js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:552:13 (libxul.so+0x69d3ce2)
[task 2021-04-06T09:13:05.005Z] 09:13:05     INFO -  PID 19690 |     #35 InternalCall /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:580:10 (libxul.so+0x69d46ff)
[task 2021-04-06T09:13:05.006Z] 09:13:05     INFO -  PID 19690 |     #36 js::CallFromStack(JSContext*, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:584:10 (libxul.so+0x69d46ff)
[task 2021-04-06T09:13:05.006Z] 09:13:05     INFO -  PID 19690 |     #37 js::jit::DoCallFallback(JSContext*, js::jit::BaselineFrame*, js::jit::ICCall_Fallback*, unsigned int, JS::Value*, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jit/BaselineIC.cpp:1841:10 (libxul.so+0x71d06d6)
[task 2021-04-06T09:13:05.007Z] 09:13:05     INFO -  PID 19690 |     #38 <null> <null> (0x7ffae8f16d28)
[task 2021-04-06T09:13:05.007Z] 09:13:05     INFO -  PID 19690 |     #39 Interpret(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:2165:17 (libxul.so+0x69bc9a2)
[task 2021-04-06T09:13:05.008Z] 09:13:05     INFO -  PID 19690 |     #40 js::RunScript(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:405:13 (libxul.so+0x69bb8cc)
[task 2021-04-06T09:13:05.008Z] 09:13:05     INFO -  PID 19690 |     #41 js::ExecuteKernel(JSContext*, JS::Handle<JSScript*>, JS::Handle<JSObject*>, JS::Handle<JS::Value>, js::AbstractFramePtr, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:772:13 (libxul.so+0x69d5eba)
[task 2021-04-06T09:13:05.009Z] 09:13:05     INFO -  PID 19690 |     #42 js::Execute(JSContext*, JS::Handle<JSScript*>, JS::Handle<JSObject*>, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:804:10 (libxul.so+0x69d60bd)
[task 2021-04-06T09:13:05.019Z] 09:13:05     INFO -  PID 19690 |     #43 EvaluateSourceBuffer<mozilla::Utf8Unit> /builds/worker/checkouts/gecko/js/src/vm/CompilationAndEvaluation.cpp:535:10 (libxul.so+0x6b16b33)
[task 2021-04-06T09:13:05.020Z] 09:13:05     INFO -  PID 19690 |     #44 JS::Evaluate(JSContext*, JS::ReadOnlyCompileOptions const&, JS::SourceText<mozilla::Utf8Unit>&, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/vm/CompilationAndEvaluation.cpp:543:10 (libxul.so+0x6b16b33)
[task 2021-04-06T09:13:05.020Z] 09:13:05     INFO -  PID 19690 |     #45 ProcessArgs(mozilla::dom::AutoJSAPI&, char**, int, XPCShellDirProvider*) /builds/worker/checkouts/gecko/js/xpconnect/src/XPCShellImpl.cpp:963:11 (libxul.so+0x1ac97c1)
[task 2021-04-06T09:13:05.021Z] 09:13:05     INFO -  PID 19690 |     #46 XRE_XPCShellMain(int, char**, char**, XREShellData const*) /builds/worker/checkouts/gecko/js/xpconnect/src/XPCShellImpl.cpp:1353:14 (libxul.so+0x1ac8215)
[task 2021-04-06T09:13:05.021Z] 09:13:05     INFO -  PID 19690 |     #47 mozilla::BootstrapImpl::XRE_XPCShellMain(int, char**, char**, XREShellData const*) /builds/worker/checkouts/gecko/toolkit/xre/Bootstrap.cpp:54:12 (libxul.so+0x68a93ee)
[task 2021-04-06T09:13:05.021Z] 09:13:05     INFO -  PID 19690 |     #48 main /builds/worker/checkouts/gecko/js/xpconnect/shell/xpcshell.cpp:78:27 (xpcshell+0xc740d)
[task 2021-04-06T09:13:05.022Z] 09:13:05     INFO -  PID 19690 |   Previous read of size 8 at 0x7b5400013c90 by thread T11:
[task 2021-04-06T09:13:05.022Z] 09:13:05     INFO -  PID 19690 |     #0 get /builds/worker/workspace/obj-build/dist/include/mozilla/RefPtr.h:286:27 (libxul.so+0xe3be1d)
[task 2021-04-06T09:13:05.022Z] 09:13:05     INFO -  PID 19690 |     #1 operator!=<mozilla::net::TRR, mozilla::net::TRR> /builds/worker/workspace/obj-build/dist/include/mozilla/RefPtr.h:515:37 (libxul.so+0xe3be1d)
[task 2021-04-06T09:13:05.023Z] 09:13:05     INFO -  PID 19690 |     #2 mozilla::net::TRRService::CompleteConfirmation(nsresult, mozilla::net::TRR*) /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:1189:27 (libxul.so+0xe3be1d)
[task 2021-04-06T09:13:05.023Z] 09:13:05     INFO -  PID 19690 |     #3 mozilla::net::TRRService::CompleteLookup(nsHostRecord*, nsresult, mozilla::net::AddrInfo*, bool, nsTSubstring<char> const&, mozilla::net::TRRSkippedReason, mozilla::net::TRR*) /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp:1245:5 (libxul.so+0xe3c1ed)
[task 2021-04-06T09:13:05.023Z] 09:13:05     INFO -  PID 19690 |     #4 non-virtual thunk to mozilla::net::TRRService::CompleteLookup(nsHostRecord*, nsresult, mozilla::net::AddrInfo*, bool, nsTSubstring<char> const&, mozilla::net::TRRSkippedReason, mozilla::net::TRR*) /builds/worker/checkouts/gecko/netwerk/dns/TRRService.cpp (libxul.so+0xe3c386)
[task 2021-04-06T09:13:05.024Z] 09:13:05     INFO -  PID 19690 |     #5 mozilla::net::TRR::FailData(nsresult) /builds/worker/checkouts/gecko/netwerk/dns/TRR.cpp:754:26 (libxul.so+0xe21644)
[task 2021-04-06T09:13:05.024Z] 09:13:05     INFO -  PID 19690 |     #6 mozilla::net::TRR::OnStopRequest(nsIRequest*, nsresult) /builds/worker/checkouts/gecko/netwerk/dns/TRR.cpp:966:3 (libxul.so+0xe2bc64)
[task 2021-04-06T09:13:05.025Z] 09:13:05     INFO -  PID 19690 |     #7 non-virtual thunk to mozilla::net::TRR::OnStopRequest(nsIRequest*, nsresult) /builds/worker/checkouts/gecko/netwerk/dns/TRR.cpp (libxul.so+0xe2bed8)
[task 2021-04-06T09:13:05.025Z] 09:13:05     INFO -  PID 19690 |     #8 mozilla::net::TRRServiceChannel::OnStopRequest(nsIRequest*, nsresult) /builds/worker/checkouts/gecko/netwerk/protocol/http/TRRServiceChannel.cpp:1211:16 (libxul.so+0x1266a3a)
[task 2021-04-06T09:13:05.025Z] 09:13:05     INFO -  PID 19690 |     #9 non-virtual thunk to mozilla::net::TRRServiceChannel::OnStopRequest(nsIRequest*, nsresult) /builds/worker/checkouts/gecko/netwerk/protocol/http/TRRServiceChannel.cpp (libxul.so+0x1266c1b)
[task 2021-04-06T09:13:05.026Z] 09:13:05     INFO -  PID 19690 |     #10 nsInputStreamPump::OnStateStop() /builds/worker/checkouts/gecko/netwerk/base/nsInputStreamPump.cpp:649:16 (libxul.so+0xd4b7b3)
[task 2021-04-06T09:13:05.026Z] 09:13:05     INFO -  PID 19690 |     #11 nsInputStreamPump::OnInputStreamReady(nsIAsyncInputStream*) /builds/worker/checkouts/gecko/netwerk/base/nsInputStreamPump.cpp:397:21 (libxul.so+0xd4a902)
[task 2021-04-06T09:13:05.026Z] 09:13:05     INFO -  PID 19690 |     #12 non-virtual thunk to nsInputStreamPump::OnInputStreamReady(nsIAsyncInputStream*) /builds/worker/checkouts/gecko/netwerk/base/nsInputStreamPump.cpp (libxul.so+0xd4ba39)
[task 2021-04-06T09:13:05.027Z] 09:13:05     INFO -  PID 19690 |     #13 nsInputStreamReadyEvent::Run() /builds/worker/checkouts/gecko/xpcom/io/nsStreamUtils.cpp:94:20 (libxul.so+0xba34fc)
[task 2021-04-06T09:13:05.027Z] 09:13:05     INFO -  PID 19690 |     #14 nsThread::ProcessNextEvent(bool, bool*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:1149:16 (libxul.so+0xbe8ffb)
[task 2021-04-06T09:13:05.027Z] 09:13:05     INFO -  PID 19690 |     #15 NS_ProcessNextEvent(nsIThread*, bool) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.cpp:548:10 (libxul.so+0xbef312)
[task 2021-04-06T09:13:05.028Z] 09:13:05     INFO -  PID 19690 |     #16 mozilla::ipc::MessagePumpForNonMainThreads::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:332:5 (libxul.so+0x14f94c8)
[task 2021-04-06T09:13:05.028Z] 09:13:05     INFO -  PID 19690 |     #17 RunInternal /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:335:10 (libxul.so+0x148308c)
[task 2021-04-06T09:13:05.029Z] 09:13:05     INFO -  PID 19690 |     #18 RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:328:3 (libxul.so+0x148308c)
[task 2021-04-06T09:13:05.029Z] 09:13:05     INFO -  PID 19690 |     #19 MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:310:3 (libxul.so+0x148308c)
[task 2021-04-06T09:13:05.029Z] 09:13:05     INFO -  PID 19690 |     #20 nsThread::ThreadFunc(void*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:391:10 (libxul.so+0xbe54e8)
[task 2021-04-06T09:13:05.030Z] 09:13:05     INFO -  PID 19690 |     #21 _pt_root /builds/worker/checkouts/gecko/nsprpub/pr/src/pthreads/ptthread.c:201:5 (libnspr4.so+0x4524b)

[Tracking Requested - why for this release]:
We should uplift this to avoid a data race

https://hg.mozilla.org/mozilla-central/rev/a3e70a270ef0

Please request Beta approval on this patch.

Comment on attachment 9213762 [details]
Bug 1703194 - Fix data race for mConfirmation.mTask, r=#necko

Beta/Release Uplift Approval Request

• User impact if declined: Could cause an unexpected outcome of TRR confirmation process.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: N/A
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This patch is quite straightforward and should not cause any issue.
• String changes made/needed: N/A

Comment on attachment 9213762 [details]
Bug 1703194 - Fix data race for mConfirmation.mTask, r=#necko

Approved for 88.0b9.

https://hg.mozilla.org/releases/mozilla-beta/rev/d74f4a1db921