get_slow with THREAD_GUARD can trigger: cannot access a Thread Local Storage value during or after destruction: AccessError

[gerwin3]

I'm trying to get to the bottom of a weird crash I'm getting. I have minimal reproducible here:

https://github.com/gerwin3/thread-local-accesserror-repro/blob/main/src/main.rs

System:

• Arch Linux x86_64 6.7.6-arch1-1
• AMD Ryzen 9 5900X

To trigger the crash: close the window with CTRL + W.

The app uses egui and tracing-appender and the combination somehow triggers an AccessError (cannot access a Thread Local Storage value during or after destruction: AccessError) that eventually is caused by a function get_slow in thread_local:

thread_local-rs/src/thread_id.rs

Line 169 in 6920311

THREAD_GUARD.with(|guard| guard.id.set(new.id));

My guess is that calling with on a thread local may not always be correct if the caller is running a destructor (?) in any case the docs of LocalKey::with seem to suggest so: https://doc.rust-lang.org/std/thread/struct.LocalKey.html#method.with

Not sure if I'm on the right track here. But since the documentation on this crate does not seem to suggest that ThreadLocal::get can panic in certain situations, and it seems it can actually panic in this case it seems this is a bug.

[aviramha]

We get this too:

(panic stuff)

   7: std::thread::local::LocalKey<T>::try_with
             at /rustc/0d8b3346a3992ab11ea35ff0fb95a6864b91f797/library/std/src/thread/local.rs:286:12
   8: std::thread::local::LocalKey<T>::with
             at /rustc/0d8b3346a3992ab11ea35ff0fb95a6864b91f797/library/std/src/thread/local.rs:262:9
   9: thread_local::thread_id::get
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/thread_local-1.1.8/src/thread_id.rs:155:13
  10: thread_local::ThreadLocal<T>::get
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/thread_local-1.1.8/src/lib.rs:185:24

(some more tracing stuff)

  17: tracing::span::Span::new_with
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tracing-0.1.40/src/span.rs:448:9
  18: tracing::span::Span::new::{{closure}}
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tracing-0.1.40/src/span.rs:437:44
  19: tracing_core::dispatcher::get_default
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tracing-core-0.1.32/src/dispatcher.rs:391:16
 20: tracing::span::Span::new
             at /home/meowjesty/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tracing-0.1.40/src/span.rs:437:9
  21: mirrord_layer::socket::ops::fcntl
             at /home/meowjesty/dev/metalbear/mirrord/mirrord/layer/src/socket/ops.rs:786:1
  22: mirrord_layer::socket::hooks::fcntl_detour
             at /home/meowjesty/dev/metalbear/mirrord/mirrord/layer/src/socket/hooks.rs:198:15
  23: <unknown>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
fatal runtime error: failed to initiate panic, error 5

It's an edge case, but perhaps need to change .with to try_with?