//test/integration:tcp_tunneling_integration_test segmentation fault on aarch64-opt (flake?)

[dio]

From this PR: #12376. Not sure if it is just a flake.

[ RUN      ] IpVersions/TcpTunnelingIntegrationTest.TcpProxyUpstreamFlush/IPv6
[2020-07-31 00:06:41.684][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:104] Caught Segmentation fault, suspect faulting address 0x61616161616179
[2020-07-31 00:06:41.684][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:91] Backtrace (use tools/stack_decode.py to get line numbers):
[2020-07-31 00:06:41.684][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:92] Envoy version: 0/1.16.0-dev/test/RELEASE/BoringSSL
[2020-07-31 00:06:41.684][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #0: __kernel_rt_sigreturn [0xffff8d7e45b8]
[2020-07-31 00:06:41.690][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #1: Envoy::Event::DispatcherImpl::runPostCallbacks() [0xe859c0]
[2020-07-31 00:06:41.695][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #2: event_process_active_single_queue [0x159f714]
[2020-07-31 00:06:41.701][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #3: event_base_loop [0x159e238]
[2020-07-31 00:06:41.706][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #4: Envoy::FakeUpstream::threadRoutine() [0x87fb44]
[2020-07-31 00:06:41.711][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #5: Envoy::Thread::ThreadImplPosix::ThreadImplPosix()::{lambda()#1}::__invoke() [0x15994f4]
[2020-07-31 00:06:41.712][21976][critical][backtrace] [bazel-out/aarch64-opt/bin/source/server/_virtual_includes/backtrace_lib/server/backtrace.h:96] #6: start_thread [0xffff8d6af088]

Runner logs: https://dev.azure.com/cncf/4684fb3d-0389-4e0b-8251-221942316e06/_apis/build/builds/46686/logs/67

[mattklein123]

This is a dup of #12253 which somehow get closed. Anyway, I've tried to repro this locally but have been haven't been able to hit it. Let's live this open to track.

[dio]

Another run (post-submit for 4f85591): https://github.com/envoyproxy/envoy/runs/934639524 with the same failure.