Panic at linked_list.rs - reborn

[chroche]

Version

> cargo tree | grep tokio

│   │   │   └── tokio v1.37.0
│   │   │       └── tokio-macros v2.2.0 (proc-macro)
│   │   │   │   ├── tokio v1.37.0 (*)
│   │   │   │   └── tokio-util v0.7.11
│   │   │   │       └── tokio v1.37.0 (*)
│   │   │   ├── tokio v1.37.0 (*)
│   │   │   │   ├── tokio v1.37.0 (*)
│   │   │   │   ├── tokio-util v0.7.11 (*)
│   │   │   │   ├── tokio v1.37.0 (*)
│   │   │   │   ├── tokio v1.37.0 (*)
│   │   │   │   └── tokio-rustls v0.24.1
│   │   │   │       └── tokio v1.37.0 (*)
│   │   │   ├── tokio v1.37.0 (*)
│   ├── tokio v1.37.0 (*)
│   │   │   ├── tokio v1.37.0 (*)
│   │   │   └── tokio-io-timeout v1.2.0
│   │   │       └── tokio v1.37.0 (*)
│   │   ├── tokio v1.37.0 (*)
│   │   ├── tokio-util v0.7.11 (*)
│   │   │   ├── tokio v1.37.0 (*)
│   │   │   ├── tokio-util v0.7.11 (*)
│       ├── tokio v1.37.0 (*)
│       ├── tokio-util v0.7.11 (*)
└── tokio v1.37.0 (*)
│   ├── tokio v1.37.0 (*)
│   ├── tokio-test v0.4.4
│   │   ├── tokio v1.37.0 (*)
│   │   └── tokio-stream v0.1.15
│   │       └── tokio v1.37.0 (*)

Platform

> uname -a

Darwin ELSLAPM-156935 21.6.0 Darwin Kernel Version 21.6.0: Wed Apr 24 06:02:02 PDT 2024; root:xnu-8020.240.18.708.4~1/RELEASE_X86_64 x86_64

Description
I seem to be able to reproduce the bug mentioned in #5782.

Error message:

thread 'main' panicked at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/util/linked_list.rs:130:9:
assertion `left != right` failed
  left: Some(0x7f8c1c826e18)
 right: Some(0x7f8c1c826e18)

The stacktrace looks like this:

   0:        0x1065dbdc5 - std::backtrace_rs::backtrace::libunwind::trace::he87ba3c236c7ad5f
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:        0x1065dbdc5 - std::backtrace_rs::backtrace::trace_unsynchronized::h3ad5d899409e49ee
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x1065dbdc5 - std::sys_common::backtrace::_print_fmt::hb1551f966d2dd86d
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:68:5
   3:        0x1065dbdc5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hbd71adb7a72f4105
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:44:22
   4:        0x1066030c3 - core::fmt::rt::Argument::fmt::h4224d647cce844bf
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/fmt/rt.rs:142:9
   5:        0x1066030c3 - core::fmt::write::h30346430340bc336
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/fmt/mod.rs:1120:17
   6:        0x1065d843e - std::io::Write::write_fmt::heb3d6316c565d5b1
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/io/mod.rs:1810:15
   7:        0x1065dbb99 - std::sys_common::backtrace::_print::hc99e5bf521524ac2
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:47:5
   8:        0x1065dbb99 - std::sys_common::backtrace::print::h67e51ff2e3d5cfbd
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:34:9
   9:        0x1065dde85 - std::panicking::default_hook::{{closure}}::hc666c9a55318d1f1
  10:        0x1065ddbfe - std::panicking::default_hook::hf980b1da49948523
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:292:9
  11:        0x104fd6f64 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hf7f87bd7c35a4244
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/alloc/src/boxed.rs:2029:9
  12:        0x104fd83be - coredump::register_panic_handler::{{closure}}::h2a03491260ffa180
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/coredump-0.1.2/src/lib.rs:215:5
  13:        0x1065de485 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h3a63db2ca77cedb5
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/alloc/src/boxed.rs:2029:9
  14:        0x1065de485 - std::panicking::rust_panic_with_hook::h683bce980186bbbe
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:783:13
  15:        0x1065de214 - std::panicking::begin_panic_handler::{{closure}}::ha6dbd11ba0ec8af1
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:657:13
  16:        0x1065dc2b9 - std::sys_common::backtrace::__rust_end_short_backtrace::h889430bddc786c98
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:171:18
  17:        0x1065ddf52 - rust_begin_unwind
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:645:5
  18:        0x10663bcb5 - core::panicking::panic_fmt::hff768cef35397791
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:72:14
  19:        0x10663c16d - core::panicking::assert_failed_inner::hc41779d852e64862
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:342:17
  20:        0x106635109 - core::panicking::assert_failed::h08df68286150560b
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/panicking.rs:297:5
  21:        0x106402f7c - tokio::util::linked_list::LinkedList<L,<L as tokio::util::linked_list::Link>::Target>::push_front::h6e00c199c3bb503f
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/util/linked_list.rs:130:9
  22:        0x10640e84d - tokio::runtime::time::wheel::level::Level::add_entry::h4a24c2925dc882a2
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/time/wheel/level.rs:207:9
  23:        0x10640ecde - tokio::runtime::time::wheel::Wheel::insert::h016cc9f1112e2ab3
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/time/wheel/mod.rs:105:13
  24:        0x106410109 - tokio::runtime::time::<impl tokio::runtime::time::handle::Handle>::reregister::h2393815bbe43b29e
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/time/mod.rs:361:32
  25:        0x10640c9ee - tokio::runtime::time::entry::TimerEntry::reset::h2f570947accf58f9
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/time/entry.rs:546:17
  26:        0x10640ca91 - tokio::runtime::time::entry::TimerEntry::poll_elapsed::had2ed4c224869068
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/time/entry.rs:564:13
  27:        0x10644b6cb - tokio::time::sleep::Sleep::poll_elapsed::h40485d45d511410e
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/time/sleep.rs:416:22
  28:        0x10644b7fc - <tokio::time::sleep::Sleep as core::future::future::Future>::poll::hd8bf0c190314fba3
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/time/sleep.rs:448:22
  29:        0x104f1cadf - asg_updater::asg::asg_update::{{closure}}::h0e4e0fa7473f8458
                               at Git/WA/usage-util-asg-updater/rust/src/asg.rs:113:50
  30:        0x104e1336a - <mapped_futures::mapped_futures::MappedFutures<K,Fut,S> as futures_core::stream::Stream>::poll_next::h4e7dd6b901e6cf01
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/mapped_futures-0.1.8/src/mapped_futures/mod.rs:745:17
  31:        0x104e13768 - futures_util::stream::stream::StreamExt::poll_next_unpin::h7d00d209d833f794
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/futures-util-0.3.30/src/stream/stream/mod.rs:1638:9
  32:        0x104f44d45 - <futures_util::stream::stream::next::Next<St> as core::future::future::Future>::poll::h38fd832dc98790a7
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/futures-util-0.3.30/src/stream/stream/next.rs:32:9
  33:        0x104dfb1ef - asg_updater::event::event_loop::{{closure}}::h19cf56f993579078
                               at Git/WA/usage-util-asg-updater/rust/src/event.rs:81:57
  34:        0x104fba400 - asg_updater::main::{{closure}}::h241100e0c7f77930
                               at Git/WA/usage-util-asg-updater/rust/src/main.rs:23:23
  35:        0x104efc8b2 - <core::pin::Pin<P> as core::future::future::Future>::poll::h40dba7c6b2c5f007
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/future/future.rs:124:9
  36:        0x104dc33be - tokio::runtime::scheduler::current_thread::CoreGuard::block_on::{{closure}}::{{closure}}::{{closure}}::haea4c2e392ff9436
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:659:57
  37:        0x104dc32f4 - tokio::runtime::coop::with_budget::h3dffaa22fc1b4bac
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/coop.rs:107:5
  38:        0x104dc32f4 - tokio::runtime::coop::budget::hfb9144f3c8e009ed
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/coop.rs:73:5
  39:        0x104dc32f4 - tokio::runtime::scheduler::current_thread::CoreGuard::block_on::{{closure}}::{{closure}}::h1d4031b3d7e1e813
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:659:25
  40:        0x104dc1f9e - tokio::runtime::scheduler::current_thread::Context::enter::hd3db13962e94ce0f
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:404:19
  41:        0x104dc2bbc - tokio::runtime::scheduler::current_thread::CoreGuard::block_on::{{closure}}::h57d7b2bbb78cd438
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:658:36
  42:        0x104dc2952 - tokio::runtime::scheduler::current_thread::CoreGuard::enter::{{closure}}::h978624809f9f6e18
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:737:68
  43:        0x104fa5b77 - tokio::runtime::context::scoped::Scoped<T>::set::h5c46c687375402be
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context/scoped.rs:40:9
  44:        0x104f45416 - tokio::runtime::context::set_scheduler::{{closure}}::hc31497bc0ef498e9
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context.rs:176:26
  45:        0x104f93d0f - std::thread::local::LocalKey<T>::try_with::hab21e96ac6a41cbf
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/thread/local.rs:270:16
  46:        0x104f934dd - std::thread::local::LocalKey<T>::with::h96b9728a141b1ae5
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/thread/local.rs:246:9
  47:        0x104f453be - tokio::runtime::context::set_scheduler::h68b9f9d631b9b79d
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context.rs:176:9
  48:        0x104dc273d - tokio::runtime::scheduler::current_thread::CoreGuard::enter::hdad653fdf22c2bda
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:737:27
  49:        0x104dc298a - tokio::runtime::scheduler::current_thread::CoreGuard::block_on::h4b2b31626abee458
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:646:19
  50:        0x104dc1a62 - tokio::runtime::scheduler::current_thread::CurrentThread::block_on::{{closure}}::h597e1d9ab7f9b01a
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:175:28
  51:        0x104f80873 - tokio::runtime::context::runtime::enter_runtime::h054a53a5a9f43219
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context/runtime.rs:65:16
  52:        0x104dc196f - tokio::runtime::scheduler::current_thread::CurrentThread::block_on::h828c6ef19337548c
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/current_thread/mod.rs:167:9
  53:        0x104f32cd0 - tokio::runtime::runtime::Runtime::block_on::h753f6fc9575d3029
                               at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/runtime.rs:349:47
  54:        0x104f9d4ed - asg_updater::main::heee9492b3ea0b59f
                               at Git/WA/usage-util-asg-updater/rust/src/main.rs:24:3
  55:        0x104e250be - core::ops::function::FnOnce::call_once::h466dcf36d152af53
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/ops/function.rs:250:5
  56:        0x104f30491 - std::sys_common::backtrace::__rust_begin_short_backtrace::hcb35513a23b57bed
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/sys_common/backtrace.rs:155:18
  57:        0x104f278a4 - std::rt::lang_start::{{closure}}::h07f7c173ba9bac23
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/rt.rs:166:18
  58:        0x1065d16e0 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h28f55c80744bada5
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/ops/function.rs:284:13
  59:        0x1065d16e0 - std::panicking::try::do_call::h2a7711271ca00d3c
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:552:40
  60:        0x1065d16e0 - std::panicking::try::h8cfa57ed24255592
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:516:19
  61:        0x1065d16e0 - std::panic::catch_unwind::h4ba1cfc637be3672
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panic.rs:142:14
  62:        0x1065d16e0 - std::rt::lang_start_internal::{{closure}}::he9dd7d8444a0863e
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/rt.rs:148:48
  63:        0x1065d16e0 - std::panicking::try::do_call::h4f92b6155a985b32
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:552:40
  64:        0x1065d16e0 - std::panicking::try::h1810f6567656aa0f
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panicking.rs:516:19
  65:        0x1065d16e0 - std::panic::catch_unwind::h979a0e4ea0734504
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/panic.rs:142:14
  66:        0x1065d16e0 - std::rt::lang_start_internal::hba631f1493ca29ca
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/rt.rs:148:20
  67:        0x104f27877 - std::rt::lang_start::h31c7b657328973db
                               at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/std/src/rt.rs:165:17
  68:        0x104f9d5a8 - _main

I can provide privately if helpful the binary that produced the crash, the associated core dump and the session logs.
Works on my MacOS Monterey 12.7.5 with

> lldb -f bin.76013 -c core.76013

(lldb) target create "bin.76013" --core "core.76013"
Core file 'core.76013' (x86_64) was loaded.
(lldb) bt
* thread #1
  * frame #0: 0x00007ff81f5d7b5e libsystem_kernel.dylib`__kill + 10
...

[Darksonn]

What dependencies are you using?

[chroche]

Hi,

attached the full Cargo tree.

[Darksonn]

Sorry I don't think there's enough information here for us to do anything.

[chroche]

What else do you think could help? Would having the core dump do?

[Darksonn]

Sorry, I have no idea what to look for in a core dump.

[name1e5s]

This panic may hit #6612

[chroche]

For what it's worth, this is what I'm able to extract from the core file:

> lldb -f bin.76013 -c /cores/core.76013

(lldb) f 12
frame #12: 0x0000000106402f7c bin.76013`tokio::util::linked_list::LinkedList$LT$L$C$$LT$L$u20$as$u20$tokio..util..linked_list..Link$GT$..Target$GT$::push_front::h6e00c199c3bb503f(self=0x00007f8c19813410, val=TimerHandle @ 0x00007ff7bb0e94c0) at linked_list.rs:130:9
   127 	        // The value should not be dropped, it is being inserted into the list
   128 	        let val = ManuallyDrop::new(val);
   129 	        let ptr = L::as_raw(&val);
-> 130 	        assert_ne!(self.head, Some(ptr));
   131 	        unsafe {
   132 	            L::pointers(ptr).as_mut().set_next(self.head);
   133 	            L::pointers(ptr).as_mut().set_prev(None);
(lldb) f 13
frame #13: 0x000000010640e84d bin.76013`tokio::runtime::time::wheel::level::Level::add_entry::h4a24c2925dc882a2(self=0x00007f8c19813220, item=TimerHandle @ 0x00007ff7bb0e9558) at level.rs:207:9
   204 	    pub(crate) unsafe fn add_entry(&mut self, item: TimerHandle) {
   205 	        let slot = slot_for(item.cached_when(), self.level);
   206
-> 207 	        self.slot[slot].push_front(item);
   208
   209 	        self.occupied |= occupied_bit(slot);
   210 	    }
(lldb) f 14
frame #14: 0x000000010640ecde bin.76013`tokio::runtime::time::wheel::Wheel::insert::h016cc9f1112e2ab3(self=0x00007f8c19707c30, item=TimerHandle @ 0x00007ff7bb0e95b0) at mod.rs:105:13
   102 	        let level = self.level_for(when);
   103
   104 	        unsafe {
-> 105 	            self.levels[level].add_entry(item);
   106 	        }
   107
   108 	        debug_assert!({
(lldb) f 15
frame #15: 0x0000000106410109 bin.76013`tokio::runtime::time::_$LT$impl$u20$tokio..runtime..time..handle..Handle$GT$::reregister::h2393815bbe43b29e(self=0x00007f8c19707c28, unpark=0x00007f8c19707bb0, new_tick=130047, entry=NonNull<tokio::runtime::time::entry::TimerShared> @ 0x00007ff7bb0e9698) at mod.rs:361:32
   358 	                // Note: We don't have to worry about racing with some other resetting
   359 	                // thread, because add_entry and reregister require exclusive control of
   360 	                // the timer entry.
-> 361 	                match unsafe { lock.wheel.insert(entry) } {
   362 	                    Ok(when) => {
   363 	                        if lock
   364 	                            .next_wake
(lldb) f 16
frame #16: 0x000000010640c9ee bin.76013`tokio::runtime::time::entry::TimerEntry::reset::h2f570947accf58f9(self=Pin<&mut tokio::runtime::time::entry::TimerEntry> @ 0x00007ff7bb0e97a0, new_time=Instant @ 0x00007ff7bb0e97b0, reregister=true) at entry.rs:546:17
   543
   544 	        if reregister {
   545 	            unsafe {
-> 546 	                self.driver()
   547 	                    .reregister(&self.driver.driver().io, tick, self.inner().into());
   548 	            }
   549 	        }
(lldb) f 17
frame #17: 0x000000010640ca91 bin.76013`tokio::runtime::time::entry::TimerEntry::poll_elapsed::had2ed4c224869068(self=Pin<&mut tokio::runtime::time::entry::TimerEntry> @ 0x00007ff7bb0e9848, cx=0x00007ff7bb1274b0) at entry.rs:564:13
   561
   562 	        if !self.registered {
   563 	            let deadline = self.deadline;
-> 564 	            self.as_mut().reset(deadline, true);
   565 	        }
   566
   567 	        let this = unsafe { self.get_unchecked_mut() };
(lldb) f 18
frame #18: 0x000000010644b6cb bin.76013`tokio::time::sleep::Sleep::poll_elapsed::h40485d45d511410e(self=Pin<&mut tokio::time::sleep::Sleep> @ 0x00007ff7bb0e98c8, cx=0x00007ff7bb1274b0) at sleep.rs:416:22
   413 	        #[cfg(any(not(tokio_unstable), not(feature = "tracing")))]
   414 	        let coop = ready!(crate::runtime::coop::poll_proceed(cx));
   415
-> 416 	        let result = me.entry.poll_elapsed(cx).map(move |r| {
   417 	            coop.made_progress();
   418 	            r
   419 	        });
(lldb) f 19
frame #19: 0x000000010644b7fc bin.76013`_$LT$tokio..time..sleep..Sleep$u20$as$u20$core..future..future..Future$GT$::poll::hd8bf0c190314fba3(self=Pin<&mut tokio::time::sleep::Sleep> @ 0x00007ff7bb0e9930, cx=0x00007ff7bb1274b0) at sleep.rs:448:22
   445 	        let _ao_span = self.inner.ctx.async_op_span.clone().entered();
   446 	        #[cfg(all(tokio_unstable, feature = "tracing"))]
   447 	        let _ao_poll_span = self.inner.ctx.async_op_poll_span.clone().entered();
-> 448 	        match ready!(self.as_mut().poll_elapsed(cx)) {
   449 	            Ok(()) => Poll::Ready(()),
   450 	            Err(e) => panic!("timer error: {}", e),
   451 	        }
(lldb) f 20
frame #20: 0x0000000104f1cadf bin.76013`asg_updater::asg::asg_update::_$u7b$$u7b$closure$u7d$$u7d$::h0e4e0fa7473f8458((null)=0x00007ff7bb1274b0) at asg.rs:113:50
   110
   111 	  if asg_name == TIMEOUT_STRING {
   112 	    trace!("Sleeping for {}s", REFRESH_INTERVAL);
-> 113 	    sleep(Duration::from_secs(REFRESH_INTERVAL)).await;
   114 	    return Ok(());
   115 	  }

BTW what I'm naively trying to do here is implement my own timeout into a MappedFutures::next() call (this crate), but it's likely not the best / correct way to do it (I'm new to this). Any advice greatly appreciated! :-)

[Darksonn]

That crate has a lot of unsafe code, a lot of yanked versions, and no public repository, so I'm not feeling so confident about it. Incorrect unsafe code in a third-party crate can easily lead to the error you are seeing, so based on that, that would be my first theory.

[chroche]

Yes I had a feeling too that this may be the root cause. I'm going to see if I can avoid using it.

Thanks!

[awused]

I'm no expert on pin/unpin magic but I think it's caused by https://github.com/StoicDeveloper/mapped_futures/blob/master/src/mapped_futures/mod.rs#L288 which inadvertently moves futures even if they're !Unpin. Changing that locally to a drop_in_place(); write(None) seems to resolve this panic. At least I can no longer consistently reproduce it.

[chroche]

I'm considering at the moment replacing Mapped Futures with the more standard StreamMap. Aren't these crates basically doing the same thing? Sorry if I'm misunderstanding something, this whole Future mechanism is getting me quite a bit confused.

Also if someone has an idea how to have a timeout when doing the .next().await call please drop me a line, I'm sure there's a native way but I can't figure out how. At the moment I'm using a dedicated async function that only does a sleep(15s) but that looks a bit grotty.

[Darksonn]

I'm going to close this because it is a bug in a third-party library.

You can add a timeout to .next().await by using tokio::time::timeout. For example:

let Ok(value) = timeout(max_dur, my_stream.next()).await else {
    // handle timeout
};

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