Lily, it looks like you've been working with these tests recently. Could you take a look at this?

Perhaps related to https://chromium-review.googlesource.com/1133692, which landed in the same range as the first failure https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/linux-chromeos-dbg/6789.

The stack is:

[ RUN      ] NetworkContextTest.PreconnectMax
[9387:9387:0712/095644.129488:9440490854:ERROR:network_service.cc(66)] Not implemented reached in std::unique_ptr network::(anonymous namespace)::CreateNetworkChangeNotifierIfNeeded()
[9387:9680:0712/095644.170847:9440532216:FATAL:lock_impl_posix.cc(103)] Check failed: rv == 0 (22 vs. 0). Invalid argument. Hint: This is often related to a use-after-free.
#0 0x7f2d4b431a6d base::debug::StackTrace::StackTrace()
#1 0x7f2d4b147b8c base::debug::StackTrace::StackTrace()
#2 0x7f2d4b1b158d logging::LogMessage::~LogMessage()
#3 0x7f2d4b457852 base::internal::LockImpl::Lock()
#4 0x000000713493 base::Lock::Acquire()
#5 0x000000713423 base::AutoLock::AutoLock()
#6 0x0000006fbbde network::(anonymous namespace)::ConnectionListener::AcceptedSocket()
#7 0x0000021b7fd9 net::test_server::EmbeddedTestServer::HandleAcceptResult()
#8 0x0000021b7d98 net::test_server::EmbeddedTestServer::OnAcceptCompleted()
#9 0x00000081a34f _ZN4base8internal13FunctorTraitsIMN7network12TestCallbackEFviEvE6InvokeIS5_PS3_JiEEEvT_OT0_DpOT1_
#10 0x00000081a27f _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN7network12TestCallbackEFviEJPS5_iEEEvOT_DpOT0_
#11 0x0000021bbfb5 _ZN4base8internal7InvokerINS0_9BindStateIMN3net11test_server18EmbeddedTestServerEFviEJNS0_17UnretainedWrapperIS5_EEEEEFviEE7RunImplIRKS7_RKNSt3__15tupleIJS9_EEEJLm0EEEEvOT_OT0_NSG_16integer_sequenceImJXspT1_EEEEOi
#12 0x0000021bbeeb _ZN4base8internal7InvokerINS0_9BindStateIMN3net11test_server18EmbeddedTestServerEFviEJNS0_17UnretainedWrapperIS5_EEEEEFviEE3RunEPNS0_13BindStateBaseEi
#13 0x7f2d4578fdee _ZNKR4base17RepeatingCallbackIFviEE3RunEi
#14 0x7f2d45b01120 net::TCPServerSocket::OnAcceptCompleted()
#15 0x7f2d45b01bd2 _ZN4base8internal13FunctorTraitsIMN3net15TCPServerSocketEFvPNSt3__110unique_ptrINS2_12StreamSocketENS4_14default_deleteIS6_EEEERKNS_17RepeatingCallbackIFviEEEiEvE6InvokeISH_PS3_JRKSA_SF_iEEEvT_OT0_DpOT1_
#16 0x7f2d45b01aea _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIRKMN3net15TCPServerSocketEFvPNSt3__110unique_ptrINS4_12StreamSocketENS6_14default_deleteIS8_EEEERKNS_17RepeatingCallbackIFviEEEiEJPS5_RKSC_SH_iEEEvOT_DpOT0_
#17 0x7f2d45b01a49 _ZN4base8internal7InvokerINS0_9BindStateIMN3net15TCPServerSocketEFvPNSt3__110unique_ptrINS3_12StreamSocketENS5_14default_deleteIS7_EEEERKNS_17RepeatingCallbackIFviEEEiEJNS0_17UnretainedWrapperIS4_EESB_SE_EEESD_E7RunImplIRKSI_RKNS5_5tupleIJSK_SB_SE_EEEJLm0ELm1ELm2EEEEvOT_OT0_NS5_16integer_sequenceImJXspT1_EEEEOi
#18 0x7f2d45b018fb _ZN4base8internal7InvokerINS0_9BindStateIMN3net15TCPServerSocketEFvPNSt3__110unique_ptrINS3_12StreamSocketENS5_14default_deleteIS7_EEEERKNS_17RepeatingCallbackIFviEEEiEJNS0_17UnretainedWrapperIS4_EESB_SE_EEESD_E3RunEPNS0_13BindStateBaseEi
#19 0x7f2d4557414f _ZNO4base12OnceCallbackIFviEE3RunEi
#20 0x7f2d45eb51e8 net::TCPSocketPosix::AcceptCompleted()
#21 0x7f2d45eb9e20 _ZN4base8internal13FunctorTraitsIMN3net14TCPSocketPosixEFvPNSt3__110unique_ptrIS3_NS4_14default_deleteIS3_EEEEPNS2_10IPEndPointENS_12OnceCallbackIFviEEEiEvE6InvokeISG_PS3_JS9_SB_SE_iEEEvT_OT0_DpOT1_
#22 0x7f2d45eb9cd1 _ZN4base8internal12InvokeHelperILb0EvE8MakeItSoIMN3net14TCPSocketPosixEFvPNSt3__110unique_ptrIS5_NS6_14default_deleteIS5_EEEEPNS4_10IPEndPointENS_12OnceCallbackIFviEEEiEJPS5_SB_SD_SG_iEEEvOT_DpOT0_
#23 0x7f2d45eb9c27 _ZN4base8internal7InvokerINS0_9BindStateIMN3net14TCPSocketPosixEFvPNSt3__110unique_ptrIS4_NS5_14default_deleteIS4_EEEEPNS3_10IPEndPointENS_12OnceCallbackIFviEEEiEJNS0_17UnretainedWrapperIS4_EESA_SC_SF_EEESE_E7RunImplISH_NS5_5tupleIJSJ_SA_SC_SF_EEEJLm0ELm1ELm2ELm3EEEEvOT_OT0_NS5_16integer_sequenceImJXspT1_EEEEOi
#24 0x7f2d45eb9a88 _ZN4base8internal7InvokerINS0_9BindStateIMN3net14TCPSocketPosixEFvPNSt3__110unique_ptrIS4_NS5_14default_deleteIS4_EEEEPNS3_10IPEndPointENS_12OnceCallbackIFviEEEiEJNS0_17UnretainedWrapperIS4_EESA_SC_SF_EEESE_E7RunOnceEPNS0_13BindStateBaseEi
#25 0x7f2d4557414f _ZNO4base12OnceCallbackIFviEE3RunEi
#26 0x7f2d45eb2c2f net::SocketPosix::AcceptCompleted()
#27 0x7f2d45eb2959 net::SocketPosix::OnFileCanReadWithoutBlocking()
#28 0x7f2d4b474a9e base::MessagePumpLibevent::FdWatchController::OnFileCanReadWithoutBlocking()
#29 0x7f2d4b47619b base::MessagePumpLibevent::OnLibeventNotification()
#30 0x7f2d4b4c76ee event_process_active
#31 0x7f2d4b4c6d37 event_base_loop
#32 0x7f2d4b476433 base::MessagePumpLibevent::Run()
#33 0x7f2d4b1db6ae base::MessageLoop::Run()
#34 0x7f2d4b283452 base::RunLoop::Run()
#35 0x7f2d4b372319 base::Thread::Run()
#36 0x7f2d4b372e2f base::Thread::ThreadMain()
#37 0x7f2d4b46331d base::(anonymous namespace)::ThreadFunc()
#38 0x7f2d3d577184 start_thread
#39 0x7f2d3cd9503d clone

lilyhoughton@ is no longer working on Chromium.

This doesn't seem to be failing anymore... closing for now.