tokio-signal is broken on Windows since version 0.1.18

Created on 23 Mar 2019  路  5Comments  路  Source: tokio-rs/tokio

Version

tokio 0.1.18

Platform

i686-pc-windows-gnu

Subcrates

tokio-signal

Description

Recent changes to tokio-signal broke it under Windows and causes a panic. See attached backtrace.
I think it is related to commit cb55bf4012a0a43efe9dd436c079924acdcd0c1c.

To reproduce: build ctrl-c example from tokio-signal crate and run it.

Backtrace:

thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src\libcore\option.rs:345:21
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::panicking::default_hook::{{closure}}
             at src\libstd\sys_common/backtrace.rs:58
             at src\libstd/panicking.rs:200
   1: std::panicking::default_hook
             at src\libstd/panicking.rs:215
   2: std::panicking::rust_panic_with_hook
             at src\libstd/panicking.rs:478
   3: std::panicking::continue_panic_fmt
             at src\libstd/panicking.rs:385
   4: rust_begin_unwind
             at src\libstd/panicking.rs:312
   5: core::panicking::panic_fmt
             at src\libcore/panicking.rs:85
   6: core::panicking::panic
             at src\libcore/panicking.rs:49
   7: <core::option::Option<T>>::unwrap
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libcore\macros.rs:10
   8: tokio_signal::windows::global_init
             at src/windows.rs:165
   9: tokio_signal::windows::Event::new::{{closure}}
             at src/windows.rs:118
  10: std::sync::once::Once::call_once::{{closure}}
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\sync\once.rs:220
  11: std::sync::once::Once::call_inner
             at src\libstd\sync/once.rs:387
  12: std::sync::once::Once::call_once
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\sync\once.rs:220
  13: tokio_signal::windows::Event::new
             at src/windows.rs:117
  14: tokio_signal::windows::Event::ctrl_c_handle
             at src/windows.rs:96
  15: tokio_signal::ctrl_c_handle::ctrl_c_imp::{{closure}}
             at src/lib.rs:137
  16: <futures::future::lazy::Lazy<F, R>>::get
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/future/lazy.rs:64
  17: <futures::future::lazy::Lazy<F, R> as futures::future::Future>::poll
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/future/lazy.rs:82
  18: <alloc::boxed::Box<F> as futures::future::Future>::poll
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/future/mod.rs:113
  19: <futures::future::flatten_stream::FlattenStream<F> as futures::stream::Stream>::poll
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/future/flatten_stream.rs:63
  20: <futures::stream::take::Take<S> as futures::stream::Stream>::poll
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/stream/take.rs:78
  21: <futures::stream::for_each::ForEach<S, F, U> as futures::future::Future>::poll
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/stream/for_each.rs:45
  22: <futures::task_impl::Spawn<T>>::poll_future_notify::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/mod.rs:326
  23: <futures::task_impl::Spawn<T>>::enter::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/mod.rs:396
  24: futures::task_impl::std::set
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/std/mod.rs:78
  25: <futures::task_impl::Spawn<T>>::enter
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/mod.rs:396
  26: <futures::task_impl::Spawn<T>>::poll_fn_notify
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/mod.rs:288
  27: <futures::task_impl::Spawn<T>>::poll_future_notify
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.1.25/src/task_impl/mod.rs:326
  28: <tokio_current_thread::Entered<'a, P>>::block_on::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:494
  29: <tokio_current_thread::Borrow<'a, U>>::enter::{{closure}}::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:788
  30: tokio_current_thread::CurrentRunner::set_spawn
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:825
  31: <tokio_current_thread::Borrow<'a, U>>::enter::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:788
  32: <std::thread::local::LocalKey<T>>::try_with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:299
  33: <std::thread::local::LocalKey<T>>::with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:245
  34: <tokio_current_thread::Borrow<'a, U>>::enter
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:786
  35: <tokio_current_thread::Entered<'a, P>>::block_on
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-current-thread-0.1.6/src/lib.rs:491
  36: tokio::runtime::current_thread::runtime::Runtime::block_on::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:200
  37: tokio::runtime::current_thread::runtime::Runtime::enter::{{closure}}::{{closure}}::{{closure}}::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:241
  38: tokio_executor::global::with_default::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-executor-0.1.7/src/global.rs:209
  39: <std::thread::local::LocalKey<T>>::try_with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:299
  40: <std::thread::local::LocalKey<T>>::with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:245
  41: tokio_executor::global::with_default
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-executor-0.1.7/src/global.rs:178
  42: tokio::runtime::current_thread::runtime::Runtime::enter::{{closure}}::{{closure}}::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:239
  43: tokio_timer::timer::handle::with_default::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-timer-0.2.10/src/timer/handle.rs:94
  44: <std::thread::local::LocalKey<T>>::try_with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:299
  45: <std::thread::local::LocalKey<T>>::with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:245
  46: tokio_timer::timer::handle::with_default
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-timer-0.2.10/src/timer/handle.rs:81
  47: tokio::runtime::current_thread::runtime::Runtime::enter::{{closure}}::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:232
  48: tokio_timer::clock::clock::with_default::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-timer-0.2.10/src/clock/clock.rs:141
  49: <std::thread::local::LocalKey<T>>::try_with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:299
  50: <std::thread::local::LocalKey<T>>::with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:245
  51: tokio_timer::clock::clock::with_default
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-timer-0.2.10/src/clock/clock.rs:124
  52: tokio::runtime::current_thread::runtime::Runtime::enter::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:231
  53: tokio_reactor::with_default::{{closure}}
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-reactor-0.1.9/src/lib.rs:237
  54: <std::thread::local::LocalKey<T>>::try_with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:299
  55: <std::thread::local::LocalKey<T>>::with
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\thread\local.rs:245
  56: tokio_reactor::with_default
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-reactor-0.1.9/src/lib.rs:217
  57: tokio::runtime::current_thread::runtime::Runtime::enter
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:230
  58: tokio::runtime::current_thread::runtime::Runtime::block_on
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/runtime.rs:198
  59: tokio::runtime::current_thread::block_on_all
             at /home/dmitry/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-0.1.18/src/runtime/current_thread/mod.rs:89
  60: ctrl_c::main
             at examples/ctrl-c.rs:56
  61: std::rt::lang_start::{{closure}}
             at /rustc/2aa4c46cfdd726e97360c2734835aa3515e8c858\src\libstd\rt.rs:64
C-bug
Source
picture ancwrd1

Most helpful comment

@Stargateur Carl has yanked the package, we'll probably publish a new version after the fix is merged in

picture ipetkov on 24 Mar 2019
🎉2 👍1

All 5 comments

The panic is thrown here: https://github.com/tokio-rs/tokio/blob/9c5cad037fd78adb087bc4734f7670d5732122c5/tokio-signal/src/windows.rs#L161-L164

I'm not super familiar with this code, but it appears that we expect things to be fully registered when invoking the PollEvented. Since we switched to a lazily initialized reactor, the inner wirings aren't guaranteed to be fully initialized (previously we used Handle::current which spun up a reactor for us, and my guess is that MyRegistration::register isn't being invoked right away).

ipetkov picture ipetkov on 23 Mar 2019

Figured out the issue, turns out we're expecting the MyRegistration::register call to create the readiness structures which are shared by the driver and the caller's task.

I was able to refactor the code pretty trivially to create the readiness structs first and pass it on to the PollEvented (which will lazily register into the reactor as needed).

I'll submit a PR for this a bit later.

On an unrelated note, the ctrl-c example still doesn't work quite right, even with the fix above, because we're blocking on all futures spawned into the runtime, which includes an immortal driver task which intercepts the OS ctrl-c events. I want to look into refactoring the driver task to possibly die on it's own if there are no more ctrl-c listeners

ipetkov picture ipetkov on 23 Mar 2019

@carllerche I think we should yank tokio-signal 0.2.8 for now since it will panic for anyone constructing signal streams without an initialized reactor

ipetkov picture ipetkov on 24 Mar 2019

@carllerche better do it, https://stackoverflow.com/questions/55325701/actix-web-example-from-introduction-gives-run-time-error-thread-main-panicked

Stargateur picture Stargateur on 24 Mar 2019
👍1

@Stargateur Carl has yanked the package, we'll probably publish a new version after the fix is merged in

ipetkov picture ipetkov on 24 Mar 2019
🎉2 👍1
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