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[docdb] TSAN Race condition between TabletPeer Init and Shutdown #3007

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bmatican opened this issue Nov 23, 2019 · 0 comments
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[docdb] TSAN Race condition between TabletPeer Init and Shutdown #3007

bmatican opened this issue Nov 23, 2019 · 0 comments
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area/docdb YugabyteDB core features kind/failing-test Tests and testing infra
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std::__1::shared_ptryb::tablet::enterprise::Tablet::get()
td::__1::shared_ptryb::consensus::RaftConsensus::get()
src/yb/tablet/tablet_peer.cc:385:17 in yb::tablet::TabletPeer::StartShutdown()
@bmatican bmatican added kind/failing-test Tests and testing infra area/docdb YugabyteDB core features labels Nov 23, 2019
@bmatican bmatican self-assigned this Nov 23, 2019
@bmatican bmatican added this to To Do in YBase features via automation Nov 23, 2019
bmatican added a commit that referenced this issue Nov 27, 2019
@bmatican
[#2978] Various TSAN fixes for QLTransactionTest.RemoteBootstrap
f9e0091 
Summary:
Started digging into some TSAN failures in QLTransactionTest.RemoteBootstrap.
Found and fixed a number of issues:

- [#3002] Data race on `yb::log::Log::active_segment_sequence_number()`
Seems this field is protected by a read lock for reads, but was not protected on writes. Turned it
into an atomic.

- [#3007] Race condition between TabletPeer `Init` and `Shutdown`
> std::__1::shared_ptr<yb::tablet::enterprise::Tablet>::get()
> td::__1::shared_ptr<yb::consensus::RaftConsensus>::get()
> src/yb/tablet/tablet_peer.cc:385:17 in yb::tablet::TabletPeer::StartShutdown()
Seems like `Shutdown` did not take the appropriate locks to access either `tablet_` or `consensus_`.

- [#3008] Race condition in thread pool `Worker` Shutdown path:
> #12 yb::rpc::ThreadPool::Impl::Shutdown() /n/users/bogdan/code/yugabyte-db/build/tsan-clang-dynamic-ninja/../../src/yb/rpc/thread_pool.cc:224 (libyrpc.so+0x20c73f)
> #3 yb::rpc::(anonymous namespace)::Worker::Notify() /n/users/bogdan/code/yugabyte-db/build/tsan-clang-dynamic-ninja/../../src/yb/rpc/thread_pool.cc:75 (libyrpc.so+0x20ad6e)
Essentially, we're destroying the vector of workers, but it's possible we still end up trying to notify
them afterwards. Moved some of the code around and expoxed an explicit `Join`. Logic should stay
basically the same. Also moved to shared_ptr instead of raw pointers.

- [#3009] Race condition in Master async RPC task vs CatalogManager reading the task description
> #0 yb::master::PickLeaderReplica::PickReplica(yb::master::TSDescriptor**) /n/users/bogdan/code/yugabyte-db/build/tsan-clang-dynamic-ninja/../../src/yb/master/async_rpc_tasks.cc:95:12 (libmaster.so+0x2450b8)
> #2 yb::master::CatalogManager::SendAddServerRequest(scoped_refptr<yb::master::TabletInfo> const&, yb::consensus::RaftPeerPB_MemberType, yb::consensus::ConsensusStatePB const&, std::__1::basic_string<char, std::__1::char_traits      <char>, std::__1::allocator<char> > const&) /n/users/bogdan/code/yugabyte-db/build/tsan-clang-dynamic-ninja/../../src/yb/master/catalog_manager.cc:5046:54
Just removed the log line..

There are a couple more issues I am still seeing:
- [#3010] Another `Long wait for safe op id`, but one seems like a bootstrap bug
Currently, doing a remote bootstrap triggers an inline OpenTablet in TSTabletManager, unlike the
normal ones, which are scheduled through a thread pool. That causes issues, because on shutdown,
we wait for the threadpool tasks to finish / get aborted. However, when done inline, this exposes
race conditions between Init and Shutdown paths for TabletPeer, RaftConsensus, Log, etc.

- [#3011] SEGV during `DisableFailureDetector`, during raft shutdown
Caused by the same race between Start (which creates the timer) and shutdown, which aborts it.

- [#3012] Log Close failures not flipping the state to closed
> F20191106 04:56:48 ../../src/yb/consensus/log_util.cc:874] Check failed: !IsFooterWritten()
Caused by the same race above. If TSTabletManager starts a remote bootstrap, we open a log. If we
shutdown the tablet manager, before finishing a bootstrap, we wipe the data, but then when we
close the log, we error out as files do not exist anymore.

- [#3013] Race condition in Master async RPC tasks state transitions
> F20191106 05:10:05 ../../src/yb/master/async_rpc_tasks.cc:126] Check failed: task_state == MonitoredTaskState::kWaiting State: kScheduling
Seems like there was a race between scheduling the task to run on the reactor thread and only AFTER
flipping the state from kScheduling. This can be a standalone investigation.

Test Plan: `ybd tsan --cxx-test client_ql-transaction-test --gtest_filter QLTransactionTest.RemoteBootstrap -n 100 --tp 4`

Reviewers: mikhail, sergei

Reviewed By: sergei

Subscribers: hector, ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D7529
YBase features automation moved this from To Do to Done Nov 27, 2019
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