TSAN: fix data race when reading a histogram's sample count

[rgs1]

Commit Message: Fix TSAN issue caused from tests when reading histograms.

Additional Description:
This was introduced by #15908. We need to read a histogram's from
the main thread to avoid data races between writes (from the main
thread) and reads (from a worker thread).

Risk Level: Low.
Testing: Unit tests + TSAN should pass.
Docs Changes: NA
Release Notes: NA
Platform Specific Features: NA

Signed-off-by: Raul Gutierrez Segales rgs@pinterest.com

[rgs1]

This should fix the TSAN issue. Happy to move the helper code that does the read from the main thread into
a helper function in test/test_common/utility.h if that's better.

cc: @antoniovicente @jmarantz

[rgs1]

/assign @antoniovicente

[antoniovicente]

Thanks!

Waiting for CI before merging.

[rgs1]

Ok the ASAN failure seems unrelated:

//test/integration:health_check_integration_test                         FAILED in 2 out of 2 in 61.7s

I'll merge main...

[rgs1]

Ok the ASAN failure seems unrelated:

//test/integration:health_check_integration_test                         FAILED in 2 out of 2 in 61.7s

I'll merge main...

Hmm nothing new in main plus it seems possibly transient:

test/integration/health_check_integration_test.cc:276: Failure
Value of: clusters_[cluster_idx].host_fake_connection_->waitForNewStream( *dispatcher_, clusters_[cluster_idx].host_stream_)
  Actual: false (Timed out waiting for new stream.)
Expected: true
Stack trace:
  0x160b9b2e: Envoy::(anonymous namespace)::HttpHealthCheckIntegrationTest_SingleEndpointImmediateHealthcheckFailHttp_Test::TestBody()
  0x208969e8: testing::internal::HandleSehExceptionsInMethodIfSupported<>()
  0x20866c13: testing::internal::HandleExceptionsInMethodIfSupported<>()
  0x20832340: testing::Test::Run()
  0x20833ad5: testing::TestInfo::Run()
... Google Test internal frames ...

[  FAILED  ] IpHttpVersions/

[rgs1]

/retest

[repokitteh-read-only]

Retrying Azure Pipelines:
Check envoy-presubmit isn't fully completed, but will still attempt retrying.
Retried failed jobs in: envoy-presubmit

🐱

Caused by: a #16946 (comment) was created by @rgs1.

see: more, trace.

[rgs1]

The remaining coverage failure is unrelated, so we can probably just merge:

  /build/tmp/_bazel_envoybuild/b570b5ccd0454dc9af9f65ab1833764d/execroot/envoy/bazel-out/k8-fastbuild/testlogs/test/exe/win32_scm_test/coverage.dat
//test/integration:health_check_integration_test                         FAILED in 38.4s

[rgs1]

/retest

[repokitteh-read-only]

Retrying Azure Pipelines:
Retried failed jobs in: envoy-presubmit

🐱

Caused by: a #16946 (comment) was created by @rgs1.

see: more, trace.

[rgs1]

cc: @phlax for visibility on the CI/coverage failure (not sure if it's a global thing)