backtrace missing from file

[matthiaskrgr]

Sometimes when rustc dumps an ICE backtrace to disk, the file only contains

rustc version: 1.73.0-nightly (0646a5d1a 2023-07-20)
platform: x86_64-unknown-linux-gnu

I have yet to find what actual file/ice causes this, its a bit tricky since there is no mapping from ice file to the actual .rs that was used to cause the ICE.

cc @estebank

[estebank]

Is this from a test case in the suite that's ICEing? I would like to try and reproduce this.

[matthiaskrgr]

It looks like this is related to panics that happen during panics:

#113211

With that file and the listed flags, you will get 3 stacktraces in stderr, but only one in the file:

thread 'rustc' panicked at 'panic in a function that cannot unwind', library/core/src/panicking.rs:126:5
stack backtrace:
   0:     0x7f47a7762eb1 - std::backtrace_rs::backtrace::libunwind::trace::h1ef044f8a76bc58e
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f47a7762eb1 - std::backtrace_rs::backtrace::trace_unsynchronized::hc89d616b4a62f3db
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f47a7762eb1 - std::sys_common::backtrace::_print_fmt::h96b055d0bb0a7069
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f47a7762eb1 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h6a9ae02f5e47ee59
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f47a77c920c - core::fmt::rt::Argument::fmt::h58c2fd6f19f6b85c
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/core/src/fmt/rt.rs:138:9
   5:     0x7f47a77c920c - core::fmt::write::he78a1e727f7f3a28
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/core/src/fmt/mod.rs:1094:21
   6:     0x7f47a77557be - std::io::Write::write_fmt::hfeb3f257b56c25f4
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/io/mod.rs:1714:15
   7:     0x7f47a7762cc5 - std::sys_common::backtrace::_print::h95d62e038e428dd1
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f47a7762cc5 - std::sys_common::backtrace::print::ha91d2cb749a45cfd
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f47a7765d1a - std::panicking::panic_hook_with_disk_dump::{{closure}}::hf44f3c5daaada0e7
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/panicking.rs:278:22
  10:     0x7f47a7765886 - std::panicking::panic_hook_with_disk_dump::hded179893093690a
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/panicking.rs:305:9
  11:     0x7f47aa973149 - rustc_driver_impl[73dfa8b3f1700d5b]::install_ice_hook::{closure#0}
  12:     0x7f47a77665c0 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h52df155e44955457
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2021:9
  13:     0x7f47a77665c0 - std::panicking::rust_panic_with_hook::h850f202a77b42b93
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/panicking.rs:733:13
  14:     0x7f47a7766301 - std::panicking::begin_panic_handler::{{closure}}::h964a2a7452a9f2bc
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/panicking.rs:619:13
  15:     0x7f47a7763316 - std::sys_common::backtrace::__rust_end_short_backtrace::h11fb79d7f7c4cd25
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys_common/backtrace.rs:151:18
  16:     0x7f47a7766092 - rust_begin_unwind
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/panicking.rs:617:5
  17:     0x7f47a77c55f3 - core::panicking::panic_nounwind_fmt::h4ac05c03e7ba0051
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/core/src/panicking.rs:96:14
  18:     0x7f47a77c5697 - core::panicking::panic_nounwind::hc5a94ab1592212b2
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/core/src/panicking.rs:126:5
  19:     0x7f47a77c5823 - core::panicking::panic_cannot_unwind::h542d29abadb0c373
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/core/src/panicking.rs:189:5
  20:     0x7f47a97fa08b - rustc_borrowck[403818351f66e70f]::mir_borrowck
  21:     0x7f47a8a5a93e - rustc_query_impl[3b38d3732de95ba4]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3b38d3732de95ba4]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 8usize]>>
  22:     0x7f47a8a5a90e - <rustc_query_impl[3b38d3732de95ba4]::query_impl::mir_borrowck::dynamic_query::{closure#2} as core[222739805fe3bed]::ops::function::FnOnce<(rustc_middle[8fd494d35938793c]::ty::context::TyCtxt, rustc_span[9451958236a7e67c]::def_id::LocalDefId)>>::call_once
  23:     0x7f47a8b3c2fd - rustc_query_system[83bbfedd71665807]::query::plumbing::try_execute_query::<rustc_query_impl[3b38d3732de95ba4]::DynamicConfig<rustc_query_system[83bbfedd71665807]::query::caches::VecCache<rustc_span[9451958236a7e67c]::def_id::LocalDefId, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[3b38d3732de95ba4]::plumbing::QueryCtxt, false>
  24:     0x7f47aa2f49ff - rustc_query_impl[3b38d3732de95ba4]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  25:     0x7f47a9b2ae3d - rustc_hir_analysis[6737c73d6b1d4c93]::collect::type_of::opaque::find_opaque_ty_constraints_for_rpit
  26:     0x7f47a9b27791 - rustc_hir_analysis[6737c73d6b1d4c93]::collect::type_of::type_of
  27:     0x7f47a8b453a3 - rustc_query_impl[3b38d3732de95ba4]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3b38d3732de95ba4]::query_impl::type_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 8usize]>>
  28:     0x7f47a8b45360 - <rustc_query_impl[3b38d3732de95ba4]::query_impl::type_of::dynamic_query::{closure#2} as core[222739805fe3bed]::ops::function::FnOnce<(rustc_middle[8fd494d35938793c]::ty::context::TyCtxt, rustc_span[9451958236a7e67c]::def_id::DefId)>>::call_once
  29:     0x7f47a8a50705 - rustc_query_system[83bbfedd71665807]::query::plumbing::try_execute_query::<rustc_query_impl[3b38d3732de95ba4]::DynamicConfig<rustc_query_system[83bbfedd71665807]::query::caches::DefaultCache<rustc_span[9451958236a7e67c]::def_id::DefId, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[3b38d3732de95ba4]::plumbing::QueryCtxt, false>
  30:     0x7f47aa2e85ef - rustc_query_impl[3b38d3732de95ba4]::query_impl::type_of::get_query_non_incr::__rust_end_short_backtrace
  31:     0x7f47a9d60736 - rustc_middle[8fd494d35938793c]::query::plumbing::query_get_at::<rustc_query_system[83bbfedd71665807]::query::caches::DefaultCache<rustc_span[9451958236a7e67c]::def_id::DefId, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 8usize]>>>
  32:     0x7f47a9d5baa7 - rustc_hir_analysis[6737c73d6b1d4c93]::check::check::check_mod_item_types
  33:     0x7f47a970a9dc - rustc_query_impl[3b38d3732de95ba4]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3b38d3732de95ba4]::query_impl::check_mod_item_types::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 0usize]>>
  34:     0x7f47a970a9be - <rustc_query_impl[3b38d3732de95ba4]::query_impl::check_mod_item_types::dynamic_query::{closure#2} as core[222739805fe3bed]::ops::function::FnOnce<(rustc_middle[8fd494d35938793c]::ty::context::TyCtxt, rustc_span[9451958236a7e67c]::def_id::LocalDefId)>>::call_once
  35:     0x7f47a91ae0ef - rustc_query_system[83bbfedd71665807]::query::plumbing::try_execute_query::<rustc_query_impl[3b38d3732de95ba4]::DynamicConfig<rustc_query_system[83bbfedd71665807]::query::caches::VecCache<rustc_span[9451958236a7e67c]::def_id::LocalDefId, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[3b38d3732de95ba4]::plumbing::QueryCtxt, false>
  36:     0x7f47aa2f2f42 - rustc_query_impl[3b38d3732de95ba4]::query_impl::check_mod_item_types::get_query_non_incr::__rust_end_short_backtrace
  37:     0x7f47a9e48d37 - <rustc_middle[8fd494d35938793c]::hir::map::Map>::for_each_module::<rustc_hir_analysis[6737c73d6b1d4c93]::check_crate::{closure#6}::{closure#0}>
  38:     0x7f47a9e4838d - <rustc_session[897f8a30474c07a2]::session::Session>::time::<(), rustc_hir_analysis[6737c73d6b1d4c93]::check_crate::{closure#6}>
  39:     0x7f47a9e480e3 - rustc_hir_analysis[6737c73d6b1d4c93]::check_crate
  40:     0x7f47a9e4787a - rustc_interface[1efc0c1d63102c92]::passes::analysis
  41:     0x7f47a9e5653a - rustc_query_impl[3b38d3732de95ba4]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3b38d3732de95ba4]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 1usize]>>
  42:     0x7f47a9e56529 - <rustc_query_impl[3b38d3732de95ba4]::query_impl::analysis::dynamic_query::{closure#2} as core[222739805fe3bed]::ops::function::FnOnce<(rustc_middle[8fd494d35938793c]::ty::context::TyCtxt, ())>>::call_once
  43:     0x7f47a9fe6c48 - rustc_query_system[83bbfedd71665807]::query::plumbing::try_execute_query::<rustc_query_impl[3b38d3732de95ba4]::DynamicConfig<rustc_query_system[83bbfedd71665807]::query::caches::SingleCache<rustc_middle[8fd494d35938793c]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[3b38d3732de95ba4]::plumbing::QueryCtxt, false>
  44:     0x7f47a9fe69d7 - rustc_query_impl[3b38d3732de95ba4]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  45:     0x7f47a9fb2025 - <rustc_middle[8fd494d35938793c]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>
  46:     0x7f47a9b9d569 - rustc_span[9451958236a7e67c]::set_source_map::<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_interface[1efc0c1d63102c92]::interface::run_compiler<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  47:     0x7f47a9b97227 - std[637671632e4d6836]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[1efc0c1d63102c92]::util::run_in_thread_pool_with_globals<rustc_interface[1efc0c1d63102c92]::interface::run_compiler<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}>::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>
  48:     0x7f47aa1d26ee - <<std[637671632e4d6836]::thread::Builder>::spawn_unchecked_<rustc_interface[1efc0c1d63102c92]::util::run_in_thread_pool_with_globals<rustc_interface[1efc0c1d63102c92]::interface::run_compiler<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}>::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#1} as core[222739805fe3bed]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  49:     0x7f47a7770cb5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h33d48cbded0f44d0
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  50:     0x7f47a7770cb5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8a3384b00ecc209a
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  51:     0x7f47a7770cb5 - std::sys::unix::thread::Thread::new::thread_start::h3b89517cd155e7bf
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys/unix/thread.rs:108:17
  52:     0x7f47a750244b - <unknown>
  53:     0x7f47a7585e40 - <unknown>
  54:                0x0 - <unknown>
c/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  56:     0x7f47a7770cb5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8a3384b00ecc209a
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  57:     0x7f47a7770cb5 - std::sys::unix::thread::Thread::new::thread_start::h3b89517cd155e7bf
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys/unix/thread.rs:108:17
  58:     0x7f47a750244b - <unknown>
  59:     0x7f47a7585e40 - <unknown>
  60:                0x0 - <unknown>
 std[637671632e4d6836]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[1efc0c1d63102c92]::util::run_in_thread_pool_with_globals<rustc_interface[1efc0c1d63102c92]::interface::run_compiler<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}>::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>
  68:     0x7f47aa1d26ee - <<std[637671632e4d6836]::thread::Builder>::spawn_unchecked_<rustc_interface[1efc0c1d63102c92]::util::run_in_thread_pool_with_globals<rustc_interface[1efc0c1d63102c92]::interface::run_compiler<core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>, rustc_driver_impl[73dfa8b3f1700d5b]::run_compiler::{closure#1}>::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[222739805fe3bed]::result::Result<(), rustc_span[9451958236a7e67c]::ErrorGuaranteed>>::{closure#1} as core[222739805fe3bed]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  69:     0x7f47a7770cb5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h33d48cbded0f44d0
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  70:     0x7f47a7770cb5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h8a3384b00ecc209a
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/alloc/src/boxed.rs:2007:9
  71:     0x7f47a7770cb5 - std::sys::unix::thread::Thread::new::thread_start::h3b89517cd155e7bf
                               at /rustc/0646a5d1aa3745cb448db247f6fa432890a1812b/library/std/src/sys/unix/thread.rs:108:17
  72:     0x7f47a750244b - <unknown>
  73:     0x7f47a7585e40 - <unknown>
  74:                0x0 - <unknown>


rustc version: 1.73.0-nightly (0646a5d1a 2023-07-20)
platform: x86_64-unknown-linux-gnu

query stack during panic:
#0 [mir_borrowck] borrow-checking `connect::{closure#0}`
#1 [mir_borrowck] borrow-checking `connect`
#2 [type_of] computing type of `connect::{opaque#0}`
#3 [check_mod_item_types] checking item types in top-level module
#4 [analysis] running analysis passes on this crate
end of query stack


query stack during panic:
#0 [mir_borrowck] borrow-checking `connect`
#1 [type_of] computing type of `connect::{opaque#0}`
#2 [check_mod_item_types] checking item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack


query stack during panic:
#0 [mir_borrowck] borrow-checking `connect`
#1 [type_of] computing type of `connect::{opaque#0}`
#2 [check_mod_item_types] checking item types in top-level module
#3 [analysis] running analysis passes on this crate
end of query stack

[matthiaskrgr]

The original finding was from one of the files in https://github.com/matthiaskrgr/glacier2/tree/master/fixed 😅

[estebank]

That actually makes sense to me, I'll have to dig into it, but it sounds like it might be straightforward to fix.

Edit: wait, re your last comment, did this new machinery regressed a previously fixed ICE, or is it an expected ICE that the new machinery didn't handle gracefully?

[matthiaskrgr]

nono, not that I know, the fixed directory is just full of files where plain rustc file.rs does not crash anymore, but icemaker can use spicy -Z flags or different executables like rustdoc, rustfmt, clippy, miri, kani, cranelift that cause ices even in the fixed directory :)

[estebank]

This happens exclusively for DelayedBugPanic because they have their own machinery to print their own (more useful) backtrace. Looking into it.

[matthiaskrgr]

Hm, I also just noticed, when for example clippy panics (you can force that with a delay_span_bug attr), we also generate an empty file :/

rustc version: 1.73.0-nightly (31395ec38 2023-07-24)
platform: x86_64-unknown-linux-gnu% 

repro

// this simulates clippy panicking due to ICE
// if we do not catch this in our CI; raise an error

#![feature(rustc_attrs)]
#[rustc_error(delay_span_bug_from_inside_query)]
fn main() {}