In https://ci.chromium.org/buildbot/chromium.fyi/Fuchsia/13424 the test triggered a crash in MockUDPClientSocket:
[00521.208] 01199.01248> <== fatal exception: process net_unittests[126982] thread initial-thread[127013]
[00521.209] 01199.01248> <== fatal page fault, PC at 0x6c6a2d244abf
[00521.210] 01199.01248> CS: 0 RIP: 0x6c6a2d244abf EFL: 0x10202 CR2: 0x28
[00521.210] 01199.01248> RAX: 0x52500d249608 RBX: 0 RCX: 0x18 RDX: 0x10
[00521.210] 01199.01248> RSI: 0x52500d249580 RDI: 0x52500d249620 RBP: 0x1 RSP: 0x1d90bc241160
[00521.210] 01199.01248> R8: 0x5209b9a4f5f8 R9: 0x51d69c187840 R10: 0x51d3880ca900 R11: 0x246
[00521.211] 01199.01248> R12: 0x5209b9a4f5f8 R13: 0x52500d249590 R14: 0x52500d2495cc R15: 0
[00521.211] 01199.01248> errc: 0x4
[00521.211] 01199.01248> bottom of user stack:
[00521.211] 01199.01248> 0x00001d90bc241160: 429a3bb3 7b8704d3 b9a51ee0 00005209 |.;.B...{.....R..|
[00521.212] 01199.01248> 0x00001d90bc241170: 00000000 00000000 bc241310 00001d90 |..........$.....|
[00521.212] 01199.01248> 0x00001d90bc241180: 00000001 00000000 2a48b538 00006c6a |........8.H*jl..|
[00521.213] 01199.01248> 0x00001d90bc241190: 00000088 00000000 f96a2c8e 00007789 |.........,j..w..|
[00521.213] 01199.01248> 0x00001d90bc2411a0: 00000000 ca11ab13 00000008 00000010 |................|
[00521.213] 01199.01248> 0x00001d90bc2411b0: 0d239740 00005250 00000000 ffffffff |@.#.PR..........|
[00521.214] 01199.01248> 0x00001d90bc2411c0: bc241208 00001d90 b9a4f0a8 00005209 |..$..........R..|
[00521.214] 01199.01248> 0x00001d90bc2411d0: 2a4b4da0 00006c6a 00000000 00000000 |.MK*jl..........|
[00521.214] 01199.01248> 0x00001d90bc2411e0: bc241310 00001d90 2d2db014 00006c6a |..$.......--jl..|
[00521.214] 01199.01248> 0x00001d90bc2411f0: b9a4f080 00005209 00000020 00000000 |.....R.. .......|
[00521.214] 01199.01248> 0x00001d90bc241200: 00000000 00000000 00000000 00000000 |................|
[00521.215] 01199.01248> 0x00001d90bc241210: bc241350 00001d90 b9a1bc80 00005209 |P.$..........R..|
[00521.215] 01199.01248> 0x00001d90bc241220: b9ab8388 00005209 bc241368 00001d90 |.....R..h.$.....|
[00521.215] 01199.01248> 0x00001d90bc241230: 00000000 00000000 2d2da7c7 00006c6a |..........--jl..|
[00521.216] 01199.01248> 0x00001d90bc241240: bc241310 00001d90 2a4b1d2c 00006c6a |..$.....,.K*jl..|
[00521.216] 01199.01248> 0x00001d90bc241250: 00000000 00000000 00000000 00000000 |................|
[00521.216] 01199.01248> arch: x86_64
[00521.217] 01199.01248> dso: id=a3cdd2f1fe5db258b9ef1b3e74e686d31ae2a1fe base=0x7789f9632000 name=libc.so
[00521.217] 01199.01248> dso: id=729ce2599dcba951 base=0x6c6a2a1ce000 name=app:net_unittests
[00521.217] 01199.01248> dso: id=520b8ffffb17b5a555fc4f3cc35a13f22647d515 base=0x697fe57f6000 name=<vDSO>
[00521.218] 01199.01248> dso: id=585b23daf740247e3f6f3f0ee413aba7a91a0f7a base=0x18a431ca2000 name=libfdio.so
[00521.218] 01199.01248> dso: id=dec38dac7bab47a972972865c166399055f7305c base=0x140f6cd73000 name=liblaunchpad.so
[00521.219] 03912.04275> [3:1398723435:0129/163100.883517:521219430:ERROR:test_launcher.cc(426)] going to zx_task_kill(job) for 5396c2eb
[00521.222] 03912.04275> [3:1398723435:0129/163100.886141:521222059:ERROR:test_launcher.cc(443)] removing 5396c2eb from live process list
#01: net::MockUDPClientSocket::MockUDPClientSocket(net::SocketDataProvider*, net::NetLog*) at ??:?
#02: net::MockClientSocketFactory::CreateDatagramClientSocket(net::DatagramSocket::BindType, base::RepeatingCallback<int (int, int)> const&, net::NetLog*, net::NetLogSource const&) at ??:?
#03: net::QuicStreamFactory::CreateSession(net::QuicStreamFactory::QuicSessionKey const&, net::QuicTransportVersion const&, int, bool, net::AddressList const&, base::TimeTicks, base::TimeTicks, net::NetLogWithSource const&, net::QuicChromiumClientSession**) at ??:?
#04: net::QuicStreamFactory::Job::DoConnect() at ??:?
#05: net::QuicStreamFactory::Job::DoLoop(int) at ??:?
#06: net::QuicStreamFactory::Job::OnResolveHostComplete(int) at ??:?
#07: net::MockHostResolverBase::ResolveNow(unsigned long) at ??:?
#08: base::debug::TaskAnnotator::RunTask(char const*, base::PendingTask*) at ??:?
#09: base::MessageLoop::RunTask(base::PendingTask*) at ??:?
#10: base::MessageLoop::DoWork() at ??:?
#11: base::MessagePumpFuchsia::Run(base::MessagePump::Delegate*) at ??:?
#12: base::RunLoop::Run() at ??:?
#13: net::internal::TestCompletionCallbackBaseInternal::WaitForResult() at ??:?
#14: net::test::QuicNetworkTransactionTest_QuicProxyConnectBadCertificate_Test::TestBody() at ??:?
#15: testing::Test::Run() at ??:?
#16: testing::TestInfo::Run() at ??:?
#17: testing::TestCase::Run() at ??:?
#18: testing::internal::UnitTestImpl::RunAllTests() at ??:?
#19: testing::UnitTest::Run() at ??:?
#20: base::TestSuite::Run() at ??:?
#21: base::(anonymous namespace)::LaunchUnitTestsInternal(base::RepeatingCallback<int ()> const&, unsigned long, int, bool, base::RepeatingCallback<void ()> const&) at ??:?
#22: base::LaunchUnitTests(int, char**, base::RepeatingCallback<int ()> const&) at ??:?
#23: main at ??:?
#24: pc 0x7789f964d10e sp 0x1d90bc242fe0 (libc.so,0x1b10e)
#25: pc 0 sp 0x1d90bc243000
In general networking tests run slowly under our current QEMU setup for Fuchsia, so this is likely a timing-related flake.
