grpc: Intermittent crash at grpc::GrpcLibraryCodegen::GrpcLibraryCodegen(bool) in grpc_library.h:45

What version of gRPC and what language are you using?

1.28.0 and 1.44.0

What operating system (Linux, Windows,…) and version?

iOS

What runtime / compiler are you using (e.g. python version or version of gcc)

Xcode 13.3, 13.4 (possibly others)

What did you do?

Issue is intermittent; no concrete steps to reproduce. One of the classes in Firestore has a grpc::CompletionQueue grpc_queue_ member variable (link). Its initialization occasionally causes a crash.

What did you expect to see?

No crash.

What did you see instead?

Intermittent crash:

Crashed: com.google.firebase.firestore
0  FirebaseFirestore              0x2ed90 grpc::GrpcLibraryCodegen::GrpcLibraryCodegen(bool) + 45 (grpc_library.h:45)
1  FirebaseFirestore              0x2ec54 grpc::CompletionQueue::CompletionQueue(grpc_completion_queue_attributes const&) + 253 (completion_queue.h:253)
2  FirebaseFirestore              0x2c954 firebase::firestore::remote::Datastore::Datastore(firebase::firestore::core::DatabaseInfo const&, std::__1::shared_ptr<firebase::firestore::util::AsyncQueue> const&, std::__1::shared_ptr<firebase::firestore::credentials::CredentialsProvider<firebase::firestore::credentials::AuthToken, firebase::firestore::credentials::User> >, std::__1::shared_ptr<firebase::firestore::credentials::CredentialsProvider<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > >, firebase::firestore::remote::ConnectivityMonitor*, firebase::firestore::remote::FirebaseMetadataProvider*) + 104 (datastore.cc:104)
3  FirebaseFirestore              0x63204 firebase::firestore::core::FirestoreClient::Initialize(firebase::firestore::credentials::User const&, firebase::firestore::api::Settings const&) + 958 (shared_ptr.h:958)
4  FirebaseFirestore              0x844c firebase::firestore::util::AsyncQueue::ExecuteBlocking(std::__1::function<void ()> const&) + 997 (atomic:997)
5  FirebaseFirestore              0x133414 firebase::firestore::util::Task::ExecuteAndRelease() + 491 (function.h:491)
6  libdispatch.dylib              0x481c _dispatch_client_callout + 20
7  libdispatch.dylib              0xc004 _dispatch_lane_serial_drain + 620
8  libdispatch.dylib              0xcc00 _dispatch_lane_invoke + 404
9  libdispatch.dylib              0x174bc _dispatch_workloop_worker_thread + 764
10 libsystem_pthread.dylib        0x37a4 _pthread_wqthread + 276
11 libsystem_pthread.dylib        0xa74c start_wqthread + 8

Anything else we should know about your project / environment?

I am from the Firestore team and am investigating this crash that was reported by a customer against Firestore. Full details are available at https://github.com/firebase/firebase-ios-sdk/issues/9462. I can’t see anything wrong with the code. This looks like a bug of some sort in grpc. Any thoughts would be greatly appreciated. Thank you!