Nightly segfaults when compiling Zenoh with non-zero opt-level

[p-avital]

Hi,

Building Zenoh in release mode with a freshly updated nightly fails with a SIGSEGV (or STATUS_ACCESS_VIOLATION on Windows). This doesn't occur on stable or beta, or when building with any profile that has opt-level=0.

I stumbled upon this while trying to measure the performance impact of #109706, which branches from master at 82bfda8 and suffers from the same issue.

Reproduction

I don't know why, but the problem only appears on zenoh (that I'm aware of): cargo +nightly build --release -p zenoh --lib fails, while any other crate within the same repo works (provided they don't depend on zenoh)?

Meta

rustc --version --verbose:

rustc 1.70.0-nightly (17c116721 2023-03-29)
binary: rustc
commit-hash: 17c11672167827b0dd92c88ef69f24346d1286dd
commit-date: 2023-03-29
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 16.0.0

The same issue arises with the same version of nightly on Windows.

Backtrace

Caused by:
  process didn't exit successfully: 
  `rustc 
    --crate-name zenoh 
    --edition=2018 
    zenoh/src/lib.rs 
    --error-format=json 
    --json=diagnostic-rendered-ansi,artifacts,future-incompat 
    --diagnostic-width=114 
    --crate-type lib 
    --emit=dep-info,metadata,link 
    -C opt-level=3 
    -C panic=abort 
    -C linker-plugin-lto 
    -C codegen-units=1 
    -C metadata=0031528ae864209c 
    -C extra-filename=-0031528ae864209c 
    --out-dir /home/pavital/git/rust/zenoh/target/release/deps
    -L dependency=/home/pavital/git/rust/zenoh/target/release/deps
    --extern async_global_executor=/home/pavital/git/rust/zenoh/target/release/deps/libasync_global_executor-1ff61112e28e1cbe.rmeta
    --extern async_std=/home/pavital/git/rust/zenoh/target/release/deps/libasync_std-988e36f19cc5e2ed.rmeta
    --extern async_trait=/home/pavital/git/rust/zenoh/target/release/deps/libasync_trait-93e7e0bbadac263e.so
    --extern base64=/home/pavital/git/rust/zenoh/target/release/deps/libbase64-ea1eeec642ade256.rmeta
    --extern env_logger=/home/pavital/git/rust/zenoh/target/release/deps/libenv_logger-8ccda1eafc995615.rmeta
    --extern event_listener=/home/pavital/git/rust/zenoh/target/release/deps/libevent_listener-3cc31ad51f48aeba.rmeta
    --extern flume=/home/pavital/git/rust/zenoh/target/release/deps/libflume-0da401bed33d29f8.rmeta
    --extern form_urlencoded=/home/pavital/git/rust/zenoh/target/release/deps/libform_urlencoded-1115dac3759b1eb9.rmeta
    --extern futures=/home/pavital/git/rust/zenoh/target/release/deps/libfutures-aeea74045a0a57a3.rmeta
    --extern git_version=/home/pavital/git/rust/zenoh/target/release/deps/libgit_version-6d4abc185706ef2a.rmeta
    --extern hex=/home/pavital/git/rust/zenoh/target/release/deps/libhex-bb0526b7e1586bc0.rmeta
    --extern lazy_static=/home/pavital/git/rust/zenoh/target/release/deps/liblazy_static-fb13441a6070ae9c.rmeta
    --extern log=/home/pavital/git/rust/zenoh/target/release/deps/liblog-19ee123d01638ee4.rmeta
    --extern ordered_float=/home/pavital/git/rust/zenoh/target/release/deps/libordered_float-f568c8820d0c7ab9.rmeta
    --extern petgraph=/home/pavital/git/rust/zenoh/target/release/deps/libpetgraph-e0fdf141ecd952f4.rmeta
    --extern rand=/home/pavital/git/rust/zenoh/target/release/deps/librand-4e2123fd0a11d27b.rmeta
    --extern regex=/home/pavital/git/rust/zenoh/target/release/deps/libregex-beca65602df09da3.rmeta
    --extern serde=/home/pavital/git/rust/zenoh/target/release/deps/libserde-0fb1376baeee33d4.rmeta
    --extern serde_json=/home/pavital/git/rust/zenoh/target/release/deps/libserde_json-a53251bca4e05b29.rmeta
    --extern socket2=/home/pavital/git/rust/zenoh/target/release/deps/libsocket2-82cb53684de5bbe7.rmeta
    --extern stop_token=/home/pavital/git/rust/zenoh/target/release/deps/libstop_token-a05424a00cf2bbf4.rmeta
    --extern uhlc=/home/pavital/git/rust/zenoh/target/release/deps/libuhlc-b2b1cc63d4b7b253.rmeta
    --extern uuid=/home/pavital/git/rust/zenoh/target/release/deps/libuuid-ba935db1ddb3f729.rmeta
    --extern vec_map=/home/pavital/git/rust/zenoh/target/release/deps/libvec_map-7a8f92fcd8ca5e85.rmeta
    --extern zenoh_buffers=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_buffers-084660677c4f0082.rmeta
    --extern zenoh_cfg_properties=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_cfg_properties-628750cc8b8f4b9b.rmeta
    --extern zenoh_codec=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_codec-a47eb37f50ae40e2.rmeta
    --extern zenoh_collections=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_collections-342b78e0301634a0.rmeta
    --extern zenoh_config=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_config-6294abe5fa7c190e.rmeta
    --extern zenoh_core=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_core-08b193df4349611e.rmeta
    --extern zenoh_crypto=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_crypto-445a326e5ed1c9f1.rmeta
    --extern zenoh_link=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_link-1e8bcec95b945ac3.rmeta
    --extern zenoh_macros=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_macros-075096dd04145b56.so
    --extern zenoh_plugin_trait=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_plugin_trait-ae545a53b834ba08.rmeta
    --extern zenoh_protocol=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_protocol-c05ff2f9ec9e06d3.rmeta
    --extern zenoh_result=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_result-2846391fcffcb2a9.rmeta
    --extern zenoh_sync=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_sync-e3e8a288f21b29c4.rmeta
    --extern zenoh_transport=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_transport-f45b981e4d814715.rmeta
    --extern zenoh_util=/home/pavital/git/rust/zenoh/target/release/deps/libzenoh_util-81eff5acfd2db5b9.rmeta`
  (signal: 11, SIGSEGV: invalid memory reference)

[lqd]

Could you check which nightly and PR caused this regression with cargo-bisect-rustc ?

[Noratrieb]

Additionally, are you able to get a backtrace with a debugger?

[p-avital]

Sure, I'll run the bisect tomorrow morning (CET).

@Nilstrieb I'll try, but if the builds don't already have debug symbols, I'm not sure how to have x.py spit them out. No need to reply if they're already in there, but if they aren't, instructions would be appreciated :)

[workingjubilee]

We do ship debug symbols, they may be in a rustup component instead of shipped by default. rustc-dev, I believe?

[p-avital]

Thanks, I'll check that out in roughly 8 hours :)

[Noratrieb]

We do always ship symbols in the same binary, but we never ship debuginfo.

[nikic]

Preliminary reduction for opt -passes=sroa: https://gist.github.com/nikic/1c606a180808a42806526ec00cee947c

[nikic]

Minimized:

define i128 @test() {
  %a = alloca i128
  store ptr null, ptr %a
  %v = load i128, ptr %a, !range !0
  ret i128 %v
}

!0 = !{i128 1, i128 0}

[nikic]

Upstream fix: llvm/llvm-project@fc6e91f

[p-avital]

@nikic Thank you so much for taking the issue, I did try bisecting, but you had located the issue by the time I made any progress :)