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Fix data race in tunnel_set/receiver_set and establish call data (#5650) #5652

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This is an automated cherry-pick of #5650

What problem does this PR solve?

Issue Number: ref #5095, close #5651

Problem Summary:

  • Data race in tunnel_set/receiver_set:
    In Some refinements of mpp_exchange_receiver_map and MPPTunnelSet #5132, it try to use the atomic variable status to protect tunnel_set/receiver_set in multiple thread read/write(MPPTask::runImpl thread to write and MPPTask::abort thread to read):
    if (status != INITIALIZING)
    throw Exception(fmt::format("The tunnel {} can not be registered, because the task is not in initializing state", tunnel->id()));
    tunnel_set->registerTunnel(MPPTaskId{task_meta.start_ts(), task_meta.task_id()}, tunnel);

    Unfortunately, it turns out not working becase the value of status can be changed after L145 and before L147
  • Data race in establish call data:
    void EstablishCallData::writeErr(const mpp::MPPDataPacket & packet)
    {
    state = ERR_HANDLE;
    if (write(packet))
    err_status = grpc::Status::OK;
    else
    err_status = grpc::Status(grpc::StatusCode::UNKNOWN, "Write error message failed for unknown reason.");
    }

    After write(packet) in L109, the call data is put back to completion queue, and it can be deleted anytime, so there is a chance that before executing L110, the call data itself has been deleted.

What is changed and how it works?

  • Add lock to protect tunnel_set and receiver_set
  • Don't access the member variable after write(packet), since write(packet) always return true, just set err_status to OK before write(packet)

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
    run random failpoint tests
  • No code

Side effects

  • Performance regression: Consumes more CPU
  • Performance regression: Consumes more Memory
  • Breaking backward compatibility

Documentation

  • Affects user behaviors
  • Contains syntax changes
  • Contains variable changes
  • Contains experimental features
  • Changes MySQL compatibility

Release note

None

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
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@ti-chi-bot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

To merge this cherry pick, it must first be approved by the collaborators.

AFTER it has been approved by collaborators, please ping the release team in a comment to request a cherry pick review.

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@ti-chi-bot ti-chi-bot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. type/cherry-pick-for-release-6.2 labels Aug 18, 2022
@windtalker windtalker closed this Aug 30, 2022
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2 participants