Long story here:

CallbackAlternativeCQ operates a thread pool which processes a
completion queue and then directly invokes the completion function in
the same thread. This thread pool is initialized on first Ref() and
unallocated on last Unref().

When running an in-process synchronous server (as we do for tests, using
this
https://github.com/google/tensorstore/blob/master/tensorstore/internal/grpc/grpc_mock.h),
called by an async() interface caller, if the async() callback happens
to drop the last reference to the grpc Channel, then the channel
shutdown will attempt to run in one of the the CallbackAlternativeCQ
threads.

This will cause a deadlock/race condition, as `CallbackAlternativeCQ` is
not designed to shutdown itself. When this deadlock happens,
`pthread_join(pthread_id_)` will return `EDEADLK` and the thread will
keep running. However `EDEADLK` is silently ignored by Join() so
`CallbackAlternativeCQ::Unref` will continue to delete the underlying
grpc_completion_queue, leading to a `SIGSEGV` later in the process.


https://github.com/grpc/grpc/blob/97ba9871324cb68b93f22fd1860934392cd476ee/src/cpp/common/completion_queue_cc.cc#L115

This adds an assert that pthread_join succeeded, which is useful as it
avoids a later SIGSEBV. Alternatively, the thread implementation could
gpr_log the errorcode before asserting.


Example backtrace of crash:

frame #0: 0x0000000194f1e868 libsystem_kernel.dylib`__pthread_kill + 8
frame #1: 0x0000000194f55cec libsystem_pthread.dylib`pthread_kill + 288
    frame #2: 0x0000000194e8e2c8 libsystem_c.dylib`abort + 180
    frame #3: 0x0000000194e8d620 libsystem_c.dylib`__assert_rtn + 272
frame #4: 0x0000000100a64f50 grpc_kvstore_test`grpc_core::(anonymous
namespace)::ThreadInternalsPosix::Join() + 188
frame #5: 0x00000001009c5dd0 grpc_kvstore_test`grpc_core::Thread::Join()
+ 56
frame #6: 0x0000000100154474 grpc_kvstore_test`grpc::(anonymous
namespace)::CallbackAlternativeCQ::Unref() + 216
frame #7: 0x0000000100154390
grpc_kvstore_test`grpc::CompletionQueue::ReleaseCallbackAlternativeCQ(grpc::CompletionQueue*)
+ 120
frame #8: 0x000000010014130c grpc_kvstore_test`grpc::Channel::~Channel()
+ 220
frame #9: 0x00000001001413c8 grpc_kvstore_test`grpc::Channel::~Channel()
+ 28
frame #10: 0x000000010014d678
grpc_kvstore_test`std::__1::default_delete<grpc::Channel>::operator()(grpc::Channel*)
const + 44
frame #11: 0x000000010014d358
grpc_kvstore_test`std::__1::__shared_ptr_pointer<grpc::Channel*,
std::__1::shared_ptr<grpc::Channel>::__shared_ptr_default_delete<grpc::Channel,
grpc::Channel>, std::__1::allocator<grpc::Channel> >::__on_zero_shared()
+ 72
frame #12: 0x000000010002ab5c
grpc_kvstore_test`std::__1::__shared_count::__release_shared() + 60
frame #13: 0x000000010002ab00
grpc_kvstore_test`std::__1::__shared_weak_count::__release_shared() + 28
frame #14: 0x000000010002aad0
grpc_kvstore_test`std::__1::shared_ptr<grpc::ServerCredentials>::~shared_ptr()
+ 56
frame #15: 0x00000001000053ec
grpc_kvstore_test`std::__1::shared_ptr<tensorstore_grpc::kvstore::grpc_gen::KvStoreService::Stub>::~shared_ptr()
+ 28
frame #16: 0x000000010014653c
grpc_kvstore_test`grpc::ClientContext::~ClientContext() + 356
frame #17: 0x0000000100146570
grpc_kvstore_test`grpc::ClientContext::~ClientContext() + 28
frame #18: 0x00000001000ab000 grpc_kvstore_test`tensorstore::(anonymous
namespace)::ReadTask::~ReadTask() + 68
frame #19: 0x00000001000aae90 grpc_kvstore_test`tensorstore::(anonymous
namespace)::ReadTask::~ReadTask() + 28
frame #20: 0x00000001000aae18
grpc_kvstore_test`tensorstore::internal::intrusive_ptr_decrement(tensorstore::internal::AtomicReferenceCount<tensorstore::(anonymous
namespace)::ReadTask> const*) + 68
frame #21: 0x00000001000aadc8 grpc_kvstore_test`void
tensorstore::internal::DefaultIntrusivePtrTraits::decrement<tensorstore::(anonymous
namespace)::ReadTask*>(tensorstore::(anonymous namespace)::ReadTask*) +
24
frame #22: 0x00000001000aad9c
grpc_kvstore_test`tensorstore::internal::IntrusivePtr<tensorstore::(anonymous
namespace)::ReadTask,
tensorstore::internal::DefaultIntrusivePtrTraits>::~IntrusivePtr() + 52
frame #23: 0x00000001000a5994
grpc_kvstore_test`tensorstore::internal::IntrusivePtr<tensorstore::(anonymous
namespace)::ReadTask,
tensorstore::internal::DefaultIntrusivePtrTraits>::~IntrusivePtr() + 28
frame #24: 0x00000001000aac24 grpc_kvstore_test`tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)::~() + 40
frame #25: 0x00000001000a6280 grpc_kvstore_test`tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)::~() + 28
frame #26: 0x00000001000a84ac
grpc_kvstore_test`std::__1::__compressed_pair_elem<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status), 0,
false>::~__compressed_pair_elem() + 28
frame #27: 0x00000001000a86c0
grpc_kvstore_test`std::__1::__compressed_pair<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status),
std::__1::allocator<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)> >::~__compressed_pair() + 28
frame #28: 0x00000001000a8694
grpc_kvstore_test`std::__1::__compressed_pair<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status),
std::__1::allocator<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)> >::~__compressed_pair() + 28
frame #29: 0x00000001000a990c
grpc_kvstore_test`std::__1::__function::__alloc_func<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status),
std::__1::allocator<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)>, void (grpc::Status)>::destroy() +
24
frame #30: 0x00000001000a7ea0
grpc_kvstore_test`std::__1::__function::__func<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status),
std::__1::allocator<tensorstore::(anonymous
namespace)::ReadTask::Start(tensorstore_grpc::kvstore::grpc_gen::KvStoreService::StubInterface*,
absl::Time)::'lambda'(grpc::Status)>, void (grpc::Status)>::destroy() +
28
frame #31: 0x00000001000aabbc
grpc_kvstore_test`std::__1::__function::__value_func<void
(grpc::Status)>::~__value_func() + 68
frame #32: 0x00000001000aab68
grpc_kvstore_test`std::__1::__function::__value_func<void
(grpc::Status)>::~__value_func() + 28
frame #33: 0x00000001000aab3c grpc_kvstore_test`std::__1::function<void
(grpc::Status)>::~function() + 28
frame #34: 0x00000001000a6254 grpc_kvstore_test`std::__1::function<void
(grpc::Status)>::~function() + 28
frame #35: 0x0000000100108ae0
grpc_kvstore_test`grpc::internal::CallbackWithStatusTag::Run(bool) + 368
frame #36: 0x0000000100108964
grpc_kvstore_test`grpc::internal::CallbackWithStatusTag::StaticRun(grpc_completion_queue_functor*,
int) + 44
frame #37: 0x0000000100154cb0 grpc_kvstore_test`grpc::(anonymous
namespace)::CallbackAlternativeCQ::ThreadLoop(void*) + 356
frame #38: 0x0000000100a650b8 grpc_kvstore_test`grpc_core::(anonymous
namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void
(*)(void*), void*, bool*, grpc_core::Thread::Options
const&)::'lambda'(void*)::operator()(void*) const + 240
frame #39: 0x0000000100a64fbc grpc_kvstore_test`grpc_core::(anonymous
namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void
(*)(void*), void*, bool*, grpc_core::Thread::Options
const&)::'lambda'(void*)::__invoke(void*) + 28
frame #40: 0x0000000194f5606c libsystem_pthread.dylib`_pthread_start +
148

…haned (grpc#37683)

Sample race - https://btx.cloud.google.com/invocations/0c4e65f2-3a38-4b4f-b67e-c53a4a4650ea/targets/%2F%2Ftest%2Fcore%2Fend2end:connectivity_test@poller%3Dpoll;config=2aed862ff4fd4384687d63aa95df415c7cb955355c2ab6dc6c6d7a9d123a76ec/log

```
WARNING: ThreadSanitizer: data race (pid=18)
  Write of size 8 at 0x72300000c318 by thread T29:
    #0 grpc_core::Chttp2ServerListener* std::__exchange(grpc_core::Chttp2ServerListener*&, grpc_core::Chttp2ServerListener*&) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/move.h:152:13 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x68c85)
    #1 grpc_core::Chttp2ServerListener* std::exchange(grpc_core::Chttp2ServerListener*&, grpc_core::Chttp2ServerListener*&) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/utility:287:14 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x68c05)
    #2 grpc_core::RefCountedPtr::reset(grpc_core::Chttp2ServerListener*) /proc/self/cwd/./src/core/lib/gprpp/ref_counted_ptr.h:126:20 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x68b32)
    #3 grpc_core::RefCountedPtr::operator=(grpc_core::RefCountedPtr&&) /proc/self/cwd/./src/core/lib/gprpp/ref_counted_ptr.h:66:5 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x54380)
    #4 grpc_core::Chttp2ServerListener::ActiveConnection::Start(grpc_core::RefCountedPtr, std::unique_ptr, grpc_core::ChannelArgs const&) /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:615:13 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x48914)
    #5 grpc_core::Chttp2ServerListener::OnAccept(void*, grpc_endpoint*, grpc_pollset*, grpc_tcp_server_acceptor*) /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:881:21 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x49ce2)
    #6 CreateEventEngineListener(grpc_tcp_server*, grpc_closure*, grpc_event_engine::experimental::EndpointConfig const&, grpc_tcp_server**)::$_2::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const /proc/self/cwd/src/core/lib/iomgr/tcp_server_posix.cc:228:11 (liblibiomgr.so+0xef627)
    #7 decltype(std::declval()(std::declval>>(), std::declval())) absl::lts_20240116::base_internal::Callable::Invoke>, grpc_event_engine::experimental::MemoryAllocator>(CreateEventEngineListener(grpc_tcp_server*, grpc_closure*, grpc_event_engine::experimental::EndpointConfig const&, grpc_tcp_server**)::$_2&, std::unique_ptr>&&, grpc_event_engine::experimental::MemoryAllocator&&) /proc/self/cwd/external/com_google_absl/absl/base/internal/invoke.h:185:12 (liblibiomgr.so+0xef3c2)
    #8 decltype(Invoker>, grpc_event_engine::experimental::MemoryAllocator>::type::Invoke(std::declval(), std::declval>>(), std::declval())) absl::lts_20240116::base_internal::invoke>, grpc_event_engine::experimental::MemoryAllocator>(CreateEventEngineListener(grpc_tcp_server*, grpc_closure*, grpc_event_engine::experimental::EndpointConfig const&, grpc_tcp_server**)::$_2&, std::unique_ptr>&&, grpc_event_engine::experimental::MemoryAllocator&&) /proc/self/cwd/external/com_google_absl/absl/base/internal/invoke.h:212:10 (liblibiomgr.so+0xef325)
    #9 void absl::lts_20240116::internal_any_invocable::InvokeR>, grpc_event_engine::experimental::MemoryAllocator, void>(CreateEventEngineListener(grpc_tcp_server*, grpc_closure*, grpc_event_engine::experimental::EndpointConfig const&, grpc_tcp_server**)::$_2&, std::unique_ptr>&&, grpc_event_engine::experimental::MemoryAllocator&&) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:132:3 (liblibiomgr.so+0xef2b5)
    #10 void absl::lts_20240116::internal_any_invocable::LocalInvoker>, grpc_event_engine::experimental::MemoryAllocator>(absl::lts_20240116::internal_any_invocable::TypeErasedState*, absl::lts_20240116::internal_any_invocable::ForwardedParameter>>::type, absl::lts_20240116::internal_any_invocable::ForwardedParameter::type) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:310:10 (liblibiomgr.so+0xef1e2)
    #11 absl::lts_20240116::internal_any_invocable::Impl>, grpc_event_engine::experimental::MemoryAllocator)>::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:868:1 (libsrc_Score_Slibposix_Uevent_Uengine.so+0xa754f)
    #12 grpc_event_engine::experimental::ThreadyEventEngine::CreateListener(absl::lts_20240116::AnyInvocable>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()::operator()() /proc/self/cwd/src/core/lib/event_engine/thready_event_engine/thready_event_engine.cc:61:15 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x27cdb)
    #13 decltype(std::declval>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>()()) absl::lts_20240116::base_internal::Callable::Invoke>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>(grpc_event_engine::experimental::ThreadyEventEngine::CreateListener(absl::lts_20240116::AnyInvocable>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&) /proc/self/cwd/external/com_google_absl/absl/base/internal/invoke.h:185:12 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x27c45)
    #14 decltype(Invoker>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>::type::Invoke(std::declval>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>())) absl::lts_20240116::base_internal::invoke>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>(grpc_event_engine::experimental::ThreadyEventEngine::CreateListener(absl::lts_20240116::AnyInvocable>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&) /proc/self/cwd/external/com_google_absl/absl/base/internal/invoke.h:212:10 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x27bf5)
    #15 void absl::lts_20240116::internal_any_invocable::InvokeR>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&, void>(grpc_event_engine::experimental::ThreadyEventEngine::CreateListener(absl::lts_20240116::AnyInvocable>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:132:3 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x27ba5)
    #16 void absl::lts_20240116::internal_any_invocable::RemoteInvoker>, grpc_event_engine::experimental::MemoryAllocator)>, absl::lts_20240116::AnyInvocable, grpc_event_engine::experimental::EndpointConfig const&, std::unique_ptr>)::$_0::operator()(std::unique_ptr>, grpc_event_engine::experimental::MemoryAllocator) const::'lambda'()&>(absl::lts_20240116::internal_any_invocable::TypeErasedState*) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:368:10 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x279cd)
    #17 absl::lts_20240116::internal_any_invocable::Impl::operator()() /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:868:1 (libtest_Score_Send2end_Slibconnectivity_Ulibrary.so+0x337ff)
    #18 grpc_core::Thread::Thread(char const*, absl::lts_20240116::AnyInvocable, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::operator()(void*) const /proc/self/cwd/./src/core/lib/gprpp/thd.h:108:15 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x2e264)
    #19 grpc_core::Thread::Thread(char const*, absl::lts_20240116::AnyInvocable, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) /proc/self/cwd/./src/core/lib/gprpp/thd.h:105:13 (libsrc_Score_Slibthready_Uevent_Uengine.so+0x2e1e9)
    #20 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::operator()(void*) const /proc/self/cwd/src/core/lib/gprpp/posix/thd.cc:148:11 (liblibgpr.so+0x1d830)
    #21 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) /proc/self/cwd/src/core/lib/gprpp/posix/thd.cc:118:9 (liblibgpr.so+0x1d659)

  Previous read of size 8 at 0x72300000c318 by main thread:
    #0 grpc_core::RefCountedPtr::operator!=(std::nullptr_t) const /proc/self/cwd/./src/core/lib/gprpp/ref_counted_ptr.h:192:50 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x52345)
    #1 grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState::~HandshakingState() /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:394:30 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x463ed)
    #2 std::enable_if::value, grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState*>::type grpc_event_engine::experimental::MemoryAllocator::New, grpc_pollset*&, std::unique_ptr, grpc_core::ChannelArgs const&>(grpc_core::RefCountedPtr&&, grpc_pollset*&, std::unique_ptr&&, grpc_core::ChannelArgs const&)::Wrapper::~Wrapper() /proc/self/cwd/include/grpc/event_engine/memory_allocator.h:117:65 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x67a1c)
    #3 std::enable_if::value, grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState*>::type grpc_event_engine::experimental::MemoryAllocator::New, grpc_pollset*&, std::unique_ptr, grpc_core::ChannelArgs const&>(grpc_core::RefCountedPtr&&, grpc_pollset*&, std::unique_ptr&&, grpc_core::ChannelArgs const&)::Wrapper::~Wrapper() /proc/self/cwd/include/grpc/event_engine/memory_allocator.h:117:27 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x67a59)
    #4 void grpc_core::UnrefDelete::operator()(grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState*) const /proc/self/cwd/./src/core/lib/gprpp/ref_counted.h:224:5 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x6449d)
    #5 grpc_core::InternallyRefCounted::Unref() /proc/self/cwd/./src/core/lib/gprpp/orphanable.h:132:7 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x52581)
    #6 grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState::Orphan() /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:407:3 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x466ac)
    #7 void grpc_core::OrphanableDelete::operator()(grpc_core::Chttp2ServerListener::ActiveConnection::HandshakingState*) /proc/self/cwd/./src/core/lib/gprpp/orphanable.h:60:8 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x653b1)
    #8 std::unique_ptr::~unique_ptr() /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unique_ptr.h:292:4 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x53ddf)
    #9 grpc_core::Chttp2ServerListener::ActiveConnection::Orphan() /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:581:1 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x487db)
    #10 void grpc_core::OrphanableDelete::operator()(grpc_core::Chttp2ServerListener::ActiveConnection*) /proc/self/cwd/./src/core/lib/gprpp/orphanable.h:60:8 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x66b01)
    #11 std::unique_ptr::~unique_ptr() /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unique_ptr.h:292:4 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x53d1f)
    #12 std::pair>::~pair() /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_pair.h:208:12 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x597f9)
    #13 void __gnu_cxx::new_allocator>>>::destroy>>(std::pair>*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/ext/new_allocator.h:152:10 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x597c1)
    #14 void std::allocator_traits>>>>::destroy>>(std::allocator>>>&, std::pair>*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/alloc_traits.h:496:8 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x59725)
    #15 std::_Rb_tree>, std::_Select1st>>, std::less, std::allocator>>>::_M_destroy_node(std::_Rb_tree_node>>*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_tree.h:642:2 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x59674)
    #16 std::_Rb_tree>, std::_Select1st>>, std::less, std::allocator>>>::_M_drop_node(std::_Rb_tree_node>>*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_tree.h:650:2 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x595f9)
    #17 std::_Rb_tree>, std::_Select1st>>, std::less, std::allocator>>>::_M_erase(std::_Rb_tree_node>>*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_tree.h:1920:4 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x5945f)
    #18 std::_Rb_tree>, std::_Select1st>>, std::less, std::allocator>>>::~_Rb_tree() /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_tree.h:1000:9 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x593c5)
    #19 std::map, std::less, std::allocator>>>::~map() /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_map.h:300:22 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x51525)
    #20 grpc_core::Chttp2ServerListener::Orphan() /proc/self/cwd/src/core/ext/transport/chttp2/server/chttp2_server.cc:923:1 (libsrc_Score_Slibgrpc_Utransport_Uchttp2_Userver.so+0x4b5dd)
    #21 void grpc_core::OrphanableDelete::operator()(grpc_core::Server::ListenerInterface*) /proc/self/cwd/./src/core/lib/gprpp/orphanable.h:60:8 (libsrc_Score_Slibchaotic_Ugood_Userver.so+0x1d0981)
    #22 std::unique_ptr::reset(grpc_core::Server::ListenerInterface*) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/unique_ptr.h:402:4 (liblibserver.so+0x1d5c21)
    #23 grpc_core::Server::StopListening() /proc/self/cwd/src/core/server/server.cc:1211:23 (liblibserver.so+0x1b9c62)
    #24 grpc_core::Server::ShutdownAndNotify(grpc_completion_queue*, void*) /proc/self/cwd/src/core/server/server.cc:1195:3 (liblibserver.so+0x1b97da)
    #25 grpc_server_shutdown_and_notify /proc/self/cwd/src/core/server/server.cc:1829:37 (liblibserver.so+0x1bf212)
    #26 grpc_core::CoreEnd2endTest::ShutdownServerAndNotify(int) /proc/self/cwd/./test/core/end2end/end2end_tests.h:459:5 (libtest_Score_Send2end_Slibconnectivity_Ulibrary.so+0x33370)
    #27 grpc_core::(anonymous namespace)::CoreEnd2endTest_RetryHttp2Test_ConnectivityWatch::RunTest() /proc/self/cwd/test/core/end2end/tests/connectivity.cc:74:3 (libtest_Score_Send2end_Slibconnectivity_Ulibrary.so+0x2ee8d)
    #28 grpc_core::(anonymous namespace)::CoreEnd2endTest_RetryHttp2Test_ConnectivityWatch::TestBody() /proc/self/cwd/test/core/end2end/tests/connectivity.cc:32:1 (libtest_Score_Send2end_Slibconnectivity_Ulibrary.so+0x2dc96)
    #29 void testing::internal::HandleSehExceptionsInMethodIfSupported(testing::Test*, void (testing::Test::*)(), char const*) /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2612:10 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x16d2dc)
    #30 void testing::internal::HandleExceptionsInMethodIfSupported(testing::Test*, void (testing::Test::*)(), char const*) /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2648:14 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x14a51d)
    #31 testing::Test::Run() /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2687:5 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x120458)
    #32 testing::TestInfo::Run() /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2836:11 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x1215f3)
    #33 testing::TestSuite::Run() /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:3015:30 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x12230c)
    #34 testing::internal::UnitTestImpl::RunAllTests() /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:5921:44 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x138142)
    #35 bool testing::internal::HandleSehExceptionsInMethodIfSupported(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2612:10 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x17508f)
    #36 bool testing::internal::HandleExceptionsInMethodIfSupported(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:2648:14 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x14e5b3)
    #37 testing::UnitTest::Run() /proc/self/cwd/external/com_google_googletest/googletest/src/gtest.cc:5485:10 (libexternal_Scom_Ugoogle_Ugoogletest_Slibgtest.so+0x13795b)
    #38 RUN_ALL_TESTS() /proc/self/cwd/external/com_google_googletest/googletest/include/gtest/gtest.h:2316:73 (libtest_Score_Send2end_Slibend2end_Utest_Umain.so+0x8457)
    #39 main /proc/self/cwd/test/core/end2end/end2end_test_main.cc:50:10 (libtest_Score_Send2end_Slibend2end_Utest_Umain.so+0x77b6)
```

We start the connection outside the critical region and that's where we supply the listener ref to the connection. There is a freak case where the connection can be orphaned due to the listener stopping to serve and the `Orphan()` would also be trying to access the listener ref resulting in a race.

Closes grpc#37683

COPYBARA_INTEGRATE_REVIEW=grpc#37683 from yashykt:FixChttp2ServerRace e3c4529
PiperOrigin-RevId: 681552145

Remove tcp_tracer in chttp2_transport since it's unused and buggy.

Fix for TSAN failure (similar to grpc#38728)  -
https://btx.cloud.google.com/invocations/97eb07c8-cf0c-4c26-a0c4-e7417adb1f23/targets/%2F%2Ftest%2Fcpp%2Fext%2Fotel:otel_tracing_test@poller%3Dpoll;config=1a7b8f82b5a4a85323c9dfbac159b038ad684a9dcca8ab0ce8fe99aa87dd2da2/log

```
WARNING: ThreadSanitizer: data race (pid=15)
  Read of size 8 at 0x726c00001588 by thread T44:
    #0 GetContext /proc/self/cwd/./src/core/lib/resource_quota/arena.h:296:9 (liblibgrpc_Utransport_Uchttp2.so+0x30af6e)
    #1 (anonymous namespace)::TcpTracerIfSampled(grpc_chttp2_stream*) /proc/self/cwd/src/core/ext/transport/chttp2/transport/chttp2_transport.cc:243:17 (liblibgrpc_Utransport_Uchttp2.so+0x30af6e)
    #2 perform_stream_op_locked(void*, absl::lts_20240722::Status) /proc/self/cwd/src/core/ext/transport/chttp2/transport/chttp2_transport.cc:1655:19 (liblibgrpc_Utransport_Uchttp2.so+0x3014aa)
    #3 grpc_combiner_continue_exec_ctx() /proc/self/cwd/src/core/lib/iomgr/combiner.cc:216:5 (liblibexec_Uctx.so+0x10d7e)
    #4 grpc_core::ExecCtx::Flush() /proc/self/cwd/src/core/lib/iomgr/exec_ctx.cc:77:17 (liblibexec_Uctx.so+0x16e45)
    #5 queue_offload(grpc_core::Combiner*)::$_0::operator()() const /proc/self/cwd/src/core/lib/iomgr/combiner.cc:165:14 (liblibexec_Uctx.so+0x13092)
    #6 void std::__invoke_impl(std::__invoke_other, queue_offload(grpc_core::Combiner*)::$_0&) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/invoke.h:60:14 (liblibexec_Uctx.so+0x13005)
    #7 std::__invoke_result::type std::__invoke(queue_offload(grpc_core::Combiner*)::$_0&) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/invoke.h:95:14 (liblibexec_Uctx.so+0x12fb5)
    #8 std::invoke_result::type std::invoke(queue_offload(grpc_core::Combiner*)::$_0&) /usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/functional:81:14 (liblibexec_Uctx.so+0x12f65)
    #9 void absl::lts_20240722::internal_any_invocable::InvokeR(queue_offload(grpc_core::Combiner*)::$_0&) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:132:3 (liblibexec_Uctx.so+0x12f05)
    #10 void absl::lts_20240722::internal_any_invocable::LocalInvoker(absl::lts_20240722::internal_any_invocable::TypeErasedState*) /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:310:10 (liblibexec_Uctx.so+0x12e22)
    #11 absl::lts_20240722::internal_any_invocable::Impl::operator()() /proc/self/cwd/external/com_google_absl/absl/functional/internal/any_invocable.h:868:1 (libsrc_Score_Slibping_Ucallbacks.so+0x260bf)
    #12 grpc_event_engine::experimental::SelfDeletingClosure::Run() /proc/self/cwd/./src/core/lib/event_engine/common_closures.h:54:5 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x501bd)
    #13 grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::Step() /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:524:14 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4a949)
    #14 grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::ThreadBody() /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:487:10 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4a013)
    #15 grpc_event_engine::experimental::WorkStealingThreadPool::WorkStealingThreadPoolImpl::StartThread()::$_0::operator()(void*) const /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:257:17 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4b489)
    #16 grpc_event_engine::experimental::WorkStealingThreadPool::WorkStealingThreadPoolImpl::StartThread()::$_0::__invoke(void*) /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:255:7 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4b429)
    #17 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::operator()(void*) const /proc/self/cwd/src/core/util/posix/thd.cc:145:11 (liblibgpr.so+0x1c2e0)
    #18 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) /proc/self/cwd/src/core/util/posix/thd.cc:115:9 (liblibgpr.so+0x1c109)

  Previous write of size 8 at 0x726c00001588 by thread T47:
    #0 void grpc_core::Arena::SetContext(grpc_core::CallTracerInterface*) /proc/self/cwd/./src/core/lib/resource_quota/arena.h:305:10 (liblibgrpc_Uclient_Uchannel.so+0x5ac294)
    #1 grpc_core::(anonymous namespace)::CreateCallAttemptTracer(grpc_core::Arena*, bool) /proc/self/cwd/src/core/client_channel/client_channel_filter.cc:2388:10 (liblibgrpc_Uclient_Uchannel.so+0x58403c)
    #2 grpc_core::ClientChannelFilter::LoadBalancedCall::LoadBalancedCall(grpc_core::ClientChannelFilter*, grpc_core::Arena*, absl::lts_20240722::AnyInvocable, bool) /proc/self/cwd/src/core/client_channel/client_channel_filter.cc:2402:11 (liblibgrpc_Uclient_Uchannel.so+0x583a98)
    #3 grpc_core::ClientChannelFilter::FilterBasedLoadBalancedCall::FilterBasedLoadBalancedCall(grpc_core::ClientChannelFilter*, grpc_call_element_args const&, grpc_polling_entity*, grpc_closure*, absl::lts_20240722::AnyInvocable, bool) /proc/self/cwd/src/core/client_channel/client_channel_filter.cc:2628:7 (liblibgrpc_Uclient_Uchannel.so+0x5864d4)
    #4 grpc_core::ClientChannelFilter::FilterBasedLoadBalancedCall* grpc_core::Arena::New, bool&>(grpc_core::ClientChannelFilter*&&, grpc_call_element_args const&, grpc_polling_entity*&, grpc_closure*&, absl::lts_20240722::AnyInvocable&&, bool&) /proc/self/cwd/./src/core/lib/resource_quota/arena.h:181:13 (liblibgrpc_Uclient_Uchannel.so+0x59459d)
    #5 grpc_core::ClientChannelFilter::CreateLoadBalancedCall(grpc_call_element_args const&, grpc_polling_entity*, grpc_closure*, absl::lts_20240722::AnyInvocable, bool) /proc/self/cwd/src/core/client_channel/client_channel_filter.cc:1142:19 (liblibgrpc_Uclient_Uchannel.so+0x578343)
    #6 grpc_core::RetryFilter::LegacyCallData::CreateLoadBalancedCall(absl::lts_20240722::AnyInvocable, bool) /proc/self/cwd/src/core/client_channel/retry_filter_legacy_call_data.cc:1635:36 (liblibgrpc_Uclient_Uchannel.so+0x5f3954)
    #7 grpc_core::RetryFilter::LegacyCallData::CallAttempt::CallAttempt(grpc_core::RetryFilter::LegacyCallData*, bool) /proc/self/cwd/src/core/client_channel/retry_filter_legacy_call_data.cc:129:21 (liblibgrpc_Uclient_Uchannel.so+0x5f2de1)
    #8 grpc_core::RefCountedPtr grpc_core::MakeRefCounted(grpc_core::RetryFilter::LegacyCallData*&&, bool&) /proc/self/cwd/./src/core/util/ref_counted_ptr.h:369:31 (liblibgrpc_Uclient_Uchannel.so+0x60ad6a)
    #9 grpc_core::RetryFilter::LegacyCallData::CreateCallAttempt(bool) /proc/self/cwd/src/core/client_channel/retry_filter_legacy_call_data.cc:1644:19 (liblibgrpc_Uclient_Uchannel.so+0x605a9b)
    #10 grpc_core::RetryFilter::LegacyCallData::StartTransparentRetry(void*, absl::lts_20240722::Status) /proc/self/cwd/src/core/client_channel/retry_filter_legacy_call_data.cc:1937:12 (liblibgrpc_Uclient_Uchannel.so+0x60600b)
    #11 exec_ctx_run(grpc_closure*) /proc/self/cwd/src/core/lib/iomgr/exec_ctx.cc:43:3 (liblibexec_Uctx.so+0x17536)
    #12 grpc_core::ExecCtx::Flush() /proc/self/cwd/src/core/lib/iomgr/exec_ctx.cc:74:9 (liblibexec_Uctx.so+0x16e29)
    #13 grpc_core::ExecCtx::~ExecCtx() /proc/self/cwd/./src/core/lib/iomgr/exec_ctx.h:137:5 (liblibgrpc++_Ubase.so+0x1647cc)
    #14 grpc_core::WorkSerializer::WorkSerializerImpl::Run() /proc/self/cwd/src/core/util/work_serializer.cc:221:1 (liblibwork_Userializer.so+0x15947)
    #15 non-virtual thunk to grpc_core::WorkSerializer::WorkSerializerImpl::Run() /proc/self/cwd/src/core/util/work_serializer.cc (liblibwork_Userializer.so+0x15b09)
    #16 grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::Step() /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:524:14 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4a949)
    #17 grpc_event_engine::experimental::WorkStealingThreadPool::ThreadState::ThreadBody() /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:487:10 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4a013)
    #18 grpc_event_engine::experimental::WorkStealingThreadPool::WorkStealingThreadPoolImpl::StartThread()::$_0::operator()(void*) const /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:257:17 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4b489)
    #19 grpc_event_engine::experimental::WorkStealingThreadPool::WorkStealingThreadPoolImpl::StartThread()::$_0::__invoke(void*) /proc/self/cwd/src/core/lib/event_engine/thread_pool/work_stealing_thread_pool.cc:255:7 (libsrc_Score_Slibevent_Uengine_Uthread_Upool.so+0x4b429)
    #20 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::operator()(void*) const /proc/self/cwd/src/core/util/posix/thd.cc:145:11 (liblibgpr.so+0x1c2e0)
    #21 grpc_core::(anonymous namespace)::ThreadInternalsPosix::ThreadInternalsPosix(char const*, void (*)(void*), void*, bool*, grpc_core::Thread::Options const&)::'lambda'(void*)::__invoke(void*) /proc/self/cwd/src/core/util/posix/thd.cc:115:9 (liblibgpr.so+0x1c109)
```

Assumed sequence of events (based on stacktrace) -
* The client application creates a new RPC.
* A ClientChannelFilter::LoadBalancedCall is created for the first attempt.
* A CallAttemptTracer is created for this first attempt and a pointer to this is saved on the arena context.
* The first attempt fails without any bytes having been sent on the wire, making this RPC eligible for transparent retries.
* A new ClientChannelFilter::LoadBalancedCall created for this new attempt.
* A new CallAttemptTracer is created for this second (transparent) attempt and a pointer is saved on the arena context.
* Around the same time as a new CallAttemptTracer is created, the chttp2 transport is performing some operations for the first stream (for example, a cancel op).

Closes grpc#39015

COPYBARA_INTEGRATE_REVIEW=grpc#39015 from yashykt:FixTcpTracer 7e3746e
PiperOrigin-RevId: 739343300