Random panics at closing file descriptors about tokio-uring

[mcseemk]

Looks like you used a debug build, hence slower. I used release since wanted to benchmark against vanilla tokio.
Anyway, looks like some race condition to me.

[JakubKoralewski]

Takes really long to run, so couldn't replicate. I'm getting a 10x slower execution time:

tokio_uring] 40.370097994s total, 40.370097ms avg per iteration

Linux 5.11.0-7620-generic #21~1626191760~21.04~55de9c3-Ubuntu SMP Tue Jul 20 22:18:55 UTC  x86_64 GNU/Linux

same speed on both stable 1.53 and rustc 1.55.0-nightly (32c9b7b09 2021-07-21)

wait got it:

> cargo run
   Compiling libc v0.2.98
   Compiling log v0.4.14
   Compiling autocfg v1.0.1
   Compiling bitflags v1.2.1
   Compiling io-uring v0.5.1
   Compiling tokio v1.9.0
   Compiling mio v0.7.13
   Compiling tokio-uring v0.1.0
   Compiling issue_35 v0.1.0 (/home/jcubed/D/projects/github/tokio_uring/issue_35)
    Finished dev [unoptimized + debuginfo] target(s) in 5.17s
     Running `target/debug/issue_35`
thread 'main' panicked at 'already borrowed: BorrowMutError', /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:151:37
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'main' panicked at 'already borrowed: BorrowMutError', /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:151:37
stack backtrace:
   0:     0x557f93a2bd10 - std::backtrace_rs::backtrace::libunwind::trace::h0f5cd2ee8b0d7274
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
   1:     0x557f93a2bd10 - std::backtrace_rs::backtrace::trace_unsynchronized::h06905b5aeda069a1
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x557f93a2bd10 - std::sys_common::backtrace::_print_fmt::h4fe4c7c875072f30
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x557f93a2bd10 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hcc0746f004a9b7ef
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:46:22
   4:     0x557f93a4623c - core::fmt::write::h9a6d9c74526a6c1b
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/fmt/mod.rs:1115:17
   5:     0x557f93a2a105 - std::io::Write::write_fmt::h23dab4cc9ce72ee2
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/io/mod.rs:1665:15
   6:     0x557f93a2dbcb - std::sys_common::backtrace::_print::h173dc702502d65d2
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:49:5
   7:     0x557f93a2dbcb - std::sys_common::backtrace::print::h61bd27c4742ba817
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:36:9
   8:     0x557f93a2dbcb - std::panicking::default_hook::{{closure}}::hcaae87f0495ae613
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:208:50
   9:     0x557f93a2d6a1 - std::panicking::default_hook::h0538e728ee080db0
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:225:9
  10:     0x557f93a2e294 - std::panicking::rust_panic_with_hook::h3039e236b6ca482c
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:622:17
  11:     0x557f93a2dd77 - std::panicking::begin_panic_handler::{{closure}}::h884fbab544ffd91c
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:519:13
  12:     0x557f93a2c20c - std::sys_common::backtrace::__rust_end_short_backtrace::hdaf2e18ba3d91210
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:141:18
  13:     0x557f93a2dcd9 - rust_begin_unwind
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:515:5
  14:     0x557f9399b0c1 - core::panicking::panic_fmt::hcf5f6d96e1dd7099
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/panicking.rs:92:14
  15:     0x557f9399b153 - core::result::unwrap_failed::he898b02f57993c42
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/result.rs:1599:5
  16:     0x557f939bcebb - core::result::Result<T,E>::expect::h45c582c987d50ae7
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/result.rs:1241:23
  17:     0x557f939bfc7f - core::cell::RefCell<T>::borrow_mut::hf5cc6f6842c0e4cc
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/cell.rs:920:9
  18:     0x557f939b9a18 - <tokio_uring::driver::op::Op<T> as core::ops::drop::Drop>::drop::he1a3b2190e33a4be
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:151:25
  19:     0x557f939c3e57 - core::ptr::drop_in_place<tokio_uring::driver::op::Op<tokio_uring::driver::close::Close>>::h8cabea38a88344ad
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ptr/mod.rs:192:1
  20:     0x557f939b953e - tokio_uring::driver::op::Op<T>::submit_with::{{closure}}::hf1ad6837c2eef9de
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:92:9
  21:     0x557f939c1ed3 - scoped_tls::ScopedKey<T>::with::hee30b8b105062fb3
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:171:13
  22:     0x557f939b8688 - tokio_uring::driver::op::Op<T>::submit_with::heb7dc42ea3bf82c7
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:64:9
  23:     0x557f939b965f - tokio_uring::driver::op::Op<T>::try_submit_with::hdeb7e4e4f1c56233
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/op.rs:101:13
  24:     0x557f939b8423 - tokio_uring::driver::close::<impl tokio_uring::driver::op::Op<tokio_uring::driver::close::Close>>::close::h948d9d6260d298e7
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/close.rs:12:9
  25:     0x557f939bdf49 - tokio_uring::driver::shared_fd::Inner::submit_close_op::hec871401e4d2f896
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/shared_fd.rs:77:24
  26:     0x557f939be152 - <tokio_uring::driver::shared_fd::Inner as core::ops::drop::Drop>::drop::h697b0108d49bb4fa
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/shared_fd.rs:140:17
  27:     0x557f939c39c7 - core::ptr::drop_in_place<tokio_uring::driver::shared_fd::Inner>::h9728f41bb80065d4
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ptr/mod.rs:192:1
  28:     0x557f939bad43 - <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop::hcde060f51870e7a0
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/alloc/src/rc.rs:1443:17
  29:     0x557f939c3bfb - core::ptr::drop_in_place<alloc::rc::Rc<tokio_uring::driver::shared_fd::Inner>>::h0b18d5f3201114ff
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ptr/mod.rs:192:1
  30:     0x557f939c3a7b - core::ptr::drop_in_place<tokio_uring::driver::shared_fd::SharedFd>::hcab60bc2e6e29681
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ptr/mod.rs:192:1
  31:     0x557f939a9b6b - core::ptr::drop_in_place<tokio_uring::fs::file::File>::hbd9dd7accb5a56f8
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ptr/mod.rs:192:1
  32:     0x557f939af312 - issue_35::compute_tokio_uring::{{closure}}::{{closure}}::{{closure}}::h385a05cc6bb307de
                               at /home/jcubed/D/projects/github/tokio_uring/issue_35/src/main.rs:16:13
  33:     0x557f939abfc9 - <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hd2d0015319e1b3ad
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/future/mod.rs:80:19
  34:     0x557f939b05ed - tokio::runtime::task::core::CoreStage<T>::poll::{{closure}}::h2613984e59cd650c
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/core.rs:147:17
  35:     0x557f939a4e65 - tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut::hc8a204cb7cbc3351
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/loom/std/unsafe_cell.rs:14:9
  36:     0x557f939b0497 - tokio::runtime::task::core::CoreStage<T>::poll::h0860bc47c2592d88
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/core.rs:137:13
  37:     0x557f939a289a - tokio::runtime::task::harness::poll_future::{{closure}}::h9ab1276b8e2be0a6
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/harness.rs:437:23
  38:     0x557f939a8803 - <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::hc5de5426a087d876
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panic.rs:347:9
  39:     0x557f939aca10 - std::panicking::try::do_call::hcc8ae6306fbad147
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:401:40
  40:     0x557f939accfd - __rust_try
  41:     0x557f939ac61a - std::panicking::try::h5376e3506060d3cf
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:365:19
  42:     0x557f939a88fa - std::panic::catch_unwind::hbf4efd4deaa58e95
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panic.rs:434:14
  43:     0x557f939a2500 - tokio::runtime::task::harness::poll_future::hc52b1723a559c7b3
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/harness.rs:424:19
  44:     0x557f939a2a32 - tokio::runtime::task::harness::Harness<T,S>::poll_inner::h0993cfbc85123c67
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/harness.rs:89:9
  45:     0x557f939a303b - tokio::runtime::task::harness::Harness<T,S>::poll::h2993f4c3fd03df91
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/harness.rs:59:15
  46:     0x557f939a7f70 - tokio::runtime::task::raw::poll::h550ed78540af3a96
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/raw.rs:113:5
  47:     0x557f939f09ef - tokio::runtime::task::raw::RawTask::poll::heef3246b1a99e888
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/raw.rs:70:18
  48:     0x557f939e2e31 - tokio::runtime::task::Notified<S>::run::h89c5994ae044e360
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/task/mod.rs:166:9
  49:     0x557f939cefbb - tokio::task::local::LocalSet::tick::{{closure}}::hccef9387a37606d4
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:532:54
  50:     0x557f939f6099 - tokio::coop::with_budget::{{closure}}::h97b1a84a6210b68e
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:106:9
  51:     0x557f939dcc4f - std::thread::local::LocalKey<T>::try_with::he0491a69d9c6717d
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/thread/local.rs:399:16
  52:     0x557f939db1ca - std::thread::local::LocalKey<T>::with::h11545f688b073fcf
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/thread/local.rs:375:9
  53:     0x557f939cef54 - tokio::coop::with_budget::hd952e15714999025
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:99:5
  54:     0x557f939cef54 - tokio::coop::budget::hebba799a4c33dbe4
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:76:5
  55:     0x557f939cef54 - tokio::task::local::LocalSet::tick::h67a7c42280706ab1
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:532:31
  56:     0x557f939ad73a - <tokio::task::local::RunUntil<T> as core::future::future::Future>::poll::{{closure}}::h1af704e44a0cfddb
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:672:16
  57:     0x557f9399bc5d - tokio::macros::scoped_tls::ScopedKey<T>::set::h09f9bf94f5c837e6
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/macros/scoped_tls.rs:61:9
  58:     0x557f939ad29a - tokio::task::local::LocalSet::with::h37102df92b19f4b3
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:573:9
  59:     0x557f939ad522 - <tokio::task::local::RunUntil<T> as core::future::future::Future>::poll::h5efca81593ad92b9
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:658:9
  60:     0x557f939ad452 - tokio::task::local::LocalSet::run_until::{{closure}}::hf990de494ceba0aa
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/task/local.rs:516:9
  61:     0x557f939aba19 - <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h906bd4bcca346bac
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/future/mod.rs:80:19
  62:     0x557f939a4c8f - <core::pin::Pin<P> as core::future::future::Future>::poll::h291f8f0294fac887
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/future/future.rs:119:9
  63:     0x557f939a0230 - tokio::runtime::basic_scheduler::Inner<P>::block_on::{{closure}}::{{closure}}::h8390bbba22e27b9c
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:208:62
  64:     0x557f939b688c - tokio::coop::with_budget::{{closure}}::h433a731ee22578bf
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:106:9
  65:     0x557f939b6141 - std::thread::local::LocalKey<T>::try_with::hdd283d5197fd4428
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/thread/local.rs:399:16
  66:     0x557f939b545d - std::thread::local::LocalKey<T>::with::hc3771dc25deeb913
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/thread/local.rs:375:9
  67:     0x557f9399fb0c - tokio::coop::with_budget::heaa5143f9822b0c7
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:99:5
  68:     0x557f9399fb0c - tokio::coop::budget::h2b35830476a50b30
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/coop.rs:76:5
  69:     0x557f9399fb0c - tokio::runtime::basic_scheduler::Inner<P>::block_on::{{closure}}::h265be2f8037a4425
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:208:39
  70:     0x557f939a0cb1 - tokio::runtime::basic_scheduler::enter::{{closure}}::h2f710f878873d055
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:299:29
  71:     0x557f9399bd5d - tokio::macros::scoped_tls::ScopedKey<T>::set::hf70b9ea9b944a749
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/macros/scoped_tls.rs:61:9
  72:     0x557f939a0c36 - tokio::runtime::basic_scheduler::enter::h42e4a968cb2f8a3a
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:299:5
  73:     0x557f9399f7eb - tokio::runtime::basic_scheduler::Inner<P>::block_on::h6378414ba08be6b4
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:197:9
  74:     0x557f939a02d4 - tokio::runtime::basic_scheduler::InnerGuard<P>::block_on::hf8c1c8ebad38505d
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:452:9
  75:     0x557f939a05c2 - tokio::runtime::basic_scheduler::BasicScheduler<P>::block_on::h4eeb19383ea6cb9b
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/basic_scheduler.rs:157:24
  76:     0x557f939a5218 - tokio::runtime::Runtime::block_on::h844e6f478e953b9b
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.9.0/src/runtime/mod.rs:450:46
  77:     0x557f939b6e65 - tokio_uring::runtime::Runtime::block_on::{{closure}}::h7b620cc22602be80
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/runtime.rs:84:13
  78:     0x557f939b4960 - tokio_uring::driver::Driver::with::{{closure}}::hbbea0d91e91921f4
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/mod.rs:62:37
  79:     0x557f939a8243 - scoped_tls::ScopedKey<T>::set::h43336b73ce1d5aa1
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:137:9
  80:     0x557f939b4933 - tokio_uring::driver::Driver::with::hb454d550e932c607
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/driver/mod.rs:62:9
  81:     0x557f939b6c10 - tokio_uring::runtime::Runtime::block_on::h6fbb29cdae82fe59
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/runtime.rs:71:9
  82:     0x557f939ac547 - tokio_uring::start::h6b0700e2e9ef9eae
                               at /home/jcubed/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-uring-0.1.0/src/lib.rs:132:5
  83:     0x557f9399cd25 - issue_35::main::haff31b086db3a21b
                               at /home/jcubed/D/projects/github/tokio_uring/issue_35/src/main.rs:25:5
  84:     0x557f939a8b3b - core::ops::function::FnOnce::call_once::hd749c4ef942209be
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ops/function.rs:227:5
  85:     0x557f9399c9ee - std::sys_common::backtrace::__rust_begin_short_backtrace::ha12e96f348122c61
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/sys_common/backtrace.rs:125:18
  86:     0x557f939ac451 - std::rt::lang_start::{{closure}}::h5c31d893f8b7601d
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/rt.rs:63:18
  87:     0x557f93a2e89a - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h61bcc1dec5918b7e
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/core/src/ops/function.rs:259:13
  88:     0x557f93a2e89a - std::panicking::try::do_call::h672d24f85ce22db4
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:401:40
  89:     0x557f93a2e89a - std::panicking::try::he383e7ef11604e58
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:365:19
  90:     0x557f93a2e89a - std::panic::catch_unwind::h502ac6058961e393
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panic.rs:434:14
  91:     0x557f93a2e89a - std::rt::lang_start_internal::{{closure}}::h851ee37bb5d99fdf
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/rt.rs:45:48
  92:     0x557f93a2e89a - std::panicking::try::do_call::h84f41bb3453bbd14
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:401:40
  93:     0x557f93a2e89a - std::panicking::try::h969c45dbbf2e4c94
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panicking.rs:365:19
  94:     0x557f93a2e89a - std::panic::catch_unwind::he40b1a4614f73e03
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/panic.rs:434:14
  95:     0x557f93a2e89a - std::rt::lang_start_internal::h0fbab25cccdb30d8
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/rt.rs:45:20
  96:     0x557f939ac420 - std::rt::lang_start::hbc5770458a010176
                               at /rustc/32c9b7b091534f6d80e7e85da0cd425acb6c9a79/library/std/src/rt.rs:62:5
  97:     0x557f9399cd4c - main
  98:     0x7efef40c1565 - __libc_start_main
  99:     0x557f9399b85e - _start
 100:                0x0 - <unknown>
thread panicked while panicking. aborting.

[songzhi]

In my platform, seems the problem is from /dev/urandom. When I run the code, it sometimes paused forever without any panic. When I use a regular path, it works fine and was 2.x ms each iteration slower than yours, used the release build.

My toolchain and platform is:

nightly-x86_64-unknown-linux-gnu (default)
rustc 1.55.0-nightly (32c9b7b09 2021-07-21)

Linux 5.13.4-1-MANJARO #1 SMP PREEMPT Tue Jul 20 21:25:32 UTC 2021 x86_64 GNU/Linux

[mcseemk]

On my PC the release build reading from regular text file crashes immediately with the same error, but I was not able to reproduce the crash with the debug build though.

[carllerche]

Thanks for the report. I will investigate.

[carllerche]

I think I know what is happening, but I am not sure how to reproduce reliably. I pushed a possible fix to #39, could someone give it a shot? I will try to keep trying to reproduce myself.