TSan: data race on auditHandle

ThreadSanitizer: data race/usr/local/include/c++/7.3.0/bits/move.h:199std::enable_if >, std::is_move_constructible, std::is_move_assignable >::value, void>::type std::swap(cb::audit::Audit*&, cb::audit::Audit*&)

  Write of size 8 at 0x0000009b0130 by main thread:

    #0 std::enable_if >, std::is_move_constructible, std::is_move_assignable >::value, void>::type std::swap(cb::audit::Audit*&, cb::audit::Audit*&) /usr/local/include/c++/7.3.0/bits/move.h:199 (memcached+0x0000004f335a)

    #1 std::unique_ptr >::reset(cb::audit::Audit*) /usr/local/include/c++/7.3.0/bits/unique_ptr.h:374 (memcached+0x0000004f335a)

    #2 shutdown_audit() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/mcaudit.cc:348 (memcached+0x0000004f335a)

    #3 memcached_main /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/memcached.cc:2503 (memcached+0x000000435a46)

    #4 main /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/main.cc:33 (memcached+0x00000042145e)

  Previous read of size 8 at 0x0000009b0130 by thread T8 (mutexes: write M1049192993527234104):

    #0 std::__uniq_ptr_impl >::_M_ptr() const /usr/local/include/c++/7.3.0/bits/unique_ptr.h:147 (memcached+0x0000004f3433)

    #1 std::unique_ptr >::get() const /usr/local/include/c++/7.3.0/bits/unique_ptr.h:337 (memcached+0x0000004f3433)

    #2 std::unique_ptr >::operator->() const /usr/local/include/c++/7.3.0/bits/unique_ptr.h:331 (memcached+0x0000004f3433)

    #3 stats_audit(std::function)> const&, Cookie&) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/mcaudit.cc:361 (memcached+0x0000004f3433)

    #4 stat_audit_executor /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/protocol/mcbp/stats_context.cc:446 (memcached+0x000000528f72)

    #5 StatsCommandContext::doStats() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/protocol/mcbp/stats_context.cc:850 (memcached+0x00000052a0f6)

    #6 StatsCommandContext::step() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/protocol/mcbp/stats_context.cc:780 (memcached+0x00000052af87)

    #7 SteppableCommandContext::drive() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/protocol/mcbp/steppable_command_context.cc:37 (memcached+0x0000005313e4)

    #8 stat_executor /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/mcbp_executors.cc:199 (memcached+0x0000004fa95f)

    #9 std::_Function_handler::_M_invoke(std::_Any_data const&, Cookie&) /usr/local/include/c++/7.3.0/bits/std_function.h:316 (memcached+0x000000502fc2)

    #10 std::function::operator()(Cookie&) const /usr/local/include/c++/7.3.0/bits/std_function.h:706 (memcached+0x000000501787)

    #11 execute_client_request_packet(Cookie&, cb::mcbp::Request const&) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/mcbp_executors.cc:852 (memcached+0x000000501787)

    #12 execute_request_packet(Cookie&, cb::mcbp::Request const&) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/mcbp_executors.cc:876 (memcached+0x000000501997)

    #13 Cookie::execute() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/cookie.cc:124 (memcached+0x0000004e4aeb)

    #14 StateMachine::conn_execute() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/statemachine.cc:410 (memcached+0x00000053799c)

    #15 StateMachine::execute() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/statemachine.cc:137 (memcached+0x000000539cd7)

    #16 Connection::runStateMachinery() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/connection.cc:1377 (memcached+0x0000004cae77)

    #17 Connection::runEventLoop(short) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/connection.cc:1451 (memcached+0x0000004cd66e)

    #18 run_event_loop(Connection*, short) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/connections.cc:148 (memcached+0x0000004e2f0b)

    #19 event_handler(int, short, void*) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/memcached.cc:840 (memcached+0x000000432d2d)

    #20 event_persist_closure /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1580 (libevent_core.so.2.1.8+0x000000017086)

    #21 event_process_active_single_queue /home/couchbase/jenkins/workspace/cbdeps-platform-build-old/deps/packages/build/libevent/libevent-prefix/src/libevent/event.c:1639 (libevent_core.so.2.1.8+0x000000017086)

    #22 CouchbaseThread::run() /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/platform/src/cb_pthreads.cc:58 (libplatform_so.so.0.1.0+0x000000009c5f)

    #23 platform_thread_wrap /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/platform/src/cb_pthreads.cc:71 (libplatform_so.so.0.1.0+0x000000009c5f)

    #24   (libtsan.so.0+0x000000024feb)

  Location is global 'auditHandle' of size 8 at 0x0000009b0130 (memcached+0x0000009b0130)

  Mutex M1049192993527234104 is already destroyed.

  Thread T8 'mc:worker_2' (tid=24152, running) created by main thread at:

    #0 pthread_create  (libtsan.so.0+0x0000000282a0)

    #1 cb_create_named_thread(unsigned long*, void (*)(void*), void*, int, char const*) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/platform/src/cb_pthreads.cc:109 (libplatform_so.so.0.1.0+0x00000000995b)

    #2 create_worker /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/thread.cc:111 (memcached+0x00000049da1d)

    #3 thread_init(unsigned long, event_base*, void (*)(int, short, void*)) /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/thread.cc:458 (memcached+0x00000049da1d)

    #4 memcached_main /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/memcached.cc:2457 (memcached+0x00000043573a)

    #5 main /home/couchbase/jenkins/workspace/kv_engine-master-post-commit-TSan/kv_engine/daemon/main.cc:33 (memcached+0x00000042145e)