AccessError when dropping a mpsc channel stored in a thread local

[duarten]

Version

v1.33.0

Platform

macOS and Linux.

Description

When storing a mpsc::chan in a thread local, I get an AccessError when dropping it:

thread '<unnamed>' panicked at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/local.rs:246:26:
cannot access a Thread Local Storage value during or after destruction: AccessError
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread '<unnamed>' panicked at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/local.rs:246:26:
cannot access a Thread Local Storage value during or after destruction: AccessError
stack backtrace:
   0:        0x1046b4b24 - std::backtrace_rs::backtrace::libunwind::trace::h815672f5996c9e34
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:        0x1046b4b24 - std::backtrace_rs::backtrace::trace_unsynchronized::h2e094b2d8c270437
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x1046b4b24 - std::sys_common::backtrace::_print_fmt::hae24b71afea95695
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:67:5
   3:        0x1046b4b24 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h6d4268b2ed62fb94
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:44:22
   4:        0x1044c097c - core::fmt::rt::Argument::fmt::h835101b6de0df17f
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/fmt/rt.rs:138:9
   5:        0x1044c097c - core::fmt::write::h5d55d44549819258
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/fmt/mod.rs:1094:21
   6:        0x1046b11ac - std::io::Write::write_fmt::hc515897f91abd6cf
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/io/mod.rs:1714:15
   7:        0x1046b4924 - std::sys_common::backtrace::_print::h5844dab5cfa39fca
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:47:5
   8:        0x1046b4924 - std::sys_common::backtrace::print::h2c300c1ebedfc73c
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:34:9
   9:        0x1046b5e30 - std::panicking::default_hook::{{closure}}::h0aa9be5c44269370
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:270:22
  10:        0x1046b5b80 - std::panicking::default_hook::h2c0ef097934ee9e6
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:290:9
  11:        0x1046b63fc - std::panicking::rust_panic_with_hook::h84c8637cb6e56008
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:707:13
  12:        0x1046b6204 - std::panicking::begin_panic_handler::{{closure}}::h25482adda06c7b7f
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:599:13
  13:        0x1046b4f9c - std::sys_common::backtrace::__rust_end_short_backtrace::h0c6f3beb22324a29
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:170:18
  14:        0x1046b5fb0 - rust_begin_unwind
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:595:5
  15:        0x10472ac44 - core::panicking::panic_fmt::h9072a0246ecafd14
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:67:14
  16:        0x10472af34 - core::result::unwrap_failed::hd7600d03a3086be4
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/result.rs:1652:5
  17:        0x1046ee3cc - core::result::Result<T,E>::expect::hd2106338a094706e
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/result.rs:1034:23
  18:        0x1046ee3cc - std::thread::local::LocalKey<T>::with::hbee999b7c3c237fd
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/thread/local.rs:246:9
  19:        0x1046ee3cc - tokio::runtime::context::with_scheduler::hac1d7f063edd4d44
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/context.rs:181:17
  20:        0x1046ee3cc - tokio::runtime::scheduler::multi_thread::worker::with_current::h6d404196bc8e7b01
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/scheduler/multi_thread/worker.rs:1213:5
  21:        0x1046ee3cc - tokio::runtime::scheduler::multi_thread::worker::<impl tokio::runtime::scheduler::multi_thread::handle::Handle>::schedule_task::hbe4870a7671ee892
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/scheduler/multi_thread/worker.rs:1013:9
  22:        0x1046f8574 - tokio::runtime::task::raw::RawTask::schedule::hef2762f7fc30dba4
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/task/raw.rs:205:18
  23:        0x1046f8574 - tokio::runtime::task::harness::<impl tokio::runtime::task::raw::RawTask>::wake_by_val::hab005308c524fd21
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/task/harness.rs:78:17
  24:        0x1046f8574 - tokio::runtime::task::waker::wake_by_val::h4173dc2a7952689e
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/runtime/task/waker.rs:85:5
  25:        0x1046c531c - core::task::wake::Waker::wake::he9f26a5a169f6b60
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/task/wake.rs:281:18
  26:        0x1046c531c - tokio::sync::task::atomic_waker::AtomicWaker::wake::h176f2aa71beac0ad
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/sync/task/atomic_waker.rs:307:19
  27:        0x1046c531c - tokio::sync::mpsc::chan::Tx<T,S>::wake_rx::h09a836542d958038
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/sync/mpsc/chan.rs:167:9
  28:        0x1046c531c - <tokio::sync::mpsc::chan::Tx<T,S> as core::ops::drop::Drop>::drop::ha7788990a5697371
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.33.0/src/sync/mpsc/chan.rs:216:14
  29:        0x1046c531c - core::ptr::drop_in_place<tokio::sync::mpsc::chan::Tx<u64,tokio::sync::mpsc::unbounded::Semaphore>>::h908829beab9fe900
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497:1
  30:        0x1046c531c - core::ptr::drop_in_place<tokio::sync::mpsc::unbounded::UnboundedSender<u64>>::h772a8a40fc2babfc
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ptr/mod.rs:497:1

This is because mpsc::chan::drop calls into the context.

[Darksonn]

It appears that this is because sending a wakeup accesses a thread-local. Thanks for reporting this.