rustc SIGSEGV on 1.82.0 and 1.84.0-nightly using anyhow and clap

[fence-sitter]

Saw this in a larger codebase and tried to reduce the example as much as possible. It fails when running cargo build --release but compiles normally when running cargo build.

I noted that a lot of existing SIGSEGV issues were marked as C-defective-hardware, so I replicated the issue on three different machines to try and rule that out.

Code

Cargo.toml:

[package]
name = "rustc-sigsegv"
version = "0.1.0"
edition = "2021"

[dependencies]
anyhow = "1.0.93"
clap = { version = "4.5.21", features = ["derive"] }

main.rs:

use anyhow::Context;
use clap::Parser;

#[derive(clap::Parser)]
struct Args {
    option: Options,
}

fn main() -> anyhow::Result<std::convert::Infallible> {
    let args = Args::parse();

    loop {
        // rustc crashes if the error type is `anyhow::Error` or
        // `std::convert::Infallible`. rustc does not crash if the error type is
        // `std::io::Error`.
        Ok::<(), std::convert::Infallible>(())
            .context("")
            .or_else(match args.option {
                Options::A => Err,
                // Merging these match arms stops rustc from crashing.
                Options::B => |_| Ok(()),
                Options::C => |_| Ok(()),
            })?
    }
}

#[derive(Clone, Copy, clap::ValueEnum)]
enum Options {
    /// Deleting this doc comment stops rustc from crashing.
    A,
    B,
    C,
}

Meta

Fails on stable:

rustc 1.82.0 (f6e511eec 2024-10-15)
binary: rustc
commit-hash: f6e511eec7342f59a25f7c0534f1dbea00d01b14
commit-date: 2024-10-15
host: x86_64-unknown-linux-gnu
release: 1.82.0
LLVM version: 19.1.1

Also fails on nightly:

rustc 1.84.0-nightly (5ec7d6eee 2024-11-17)
binary: rustc
commit-hash: 5ec7d6eee7e0f5236ec1559499070eaf836bc608
commit-date: 2024-11-17
host: x86_64-unknown-linux-gnu
release: 1.84.0-nightly
LLVM version: 19.1.3

Error output

error: rustc interrupted by SIGSEGV, printing backtrace

Backtrace

    Updating crates.io index
 Downloading crates ...
  Downloaded anstyle-query v1.1.2
  Downloaded is_terminal_polyfill v1.70.1
  Downloaded anstyle v1.0.10
  Downloaded heck v0.5.0
  Downloaded strsim v0.11.1
  Downloaded utf8parse v0.2.2
  Downloaded colorchoice v1.0.3
  Downloaded anstyle-parse v0.2.6
  Downloaded quote v1.0.37
  Downloaded proc-macro2 v1.0.89
  Downloaded anyhow v1.0.93
  Downloaded clap v4.5.21
  Downloaded unicode-ident v1.0.13
  Downloaded clap_derive v4.5.18
  Downloaded clap_lex v0.7.3
  Downloaded anstream v0.6.18
  Downloaded clap_builder v4.5.21
  Downloaded syn v2.0.87
   Compiling proc-macro2 v1.0.89
   Compiling unicode-ident v1.0.13
   Compiling utf8parse v0.2.2
   Compiling is_terminal_polyfill v1.70.1
   Compiling anstyle v1.0.10
   Compiling colorchoice v1.0.3
   Compiling anstyle-query v1.1.2
   Compiling clap_lex v0.7.3
   Compiling strsim v0.11.1
   Compiling heck v0.5.0
   Compiling anyhow v1.0.93
   Compiling anstyle-parse v0.2.6
   Compiling anstream v0.6.18
   Compiling clap_builder v4.5.21
   Compiling quote v1.0.37
   Compiling syn v2.0.87
   Compiling clap_derive v4.5.18
   Compiling clap v4.5.21
   Compiling rustc-sigsegv v0.1.0 (/)
error: rustc interrupted by SIGSEGV, printing backtrace

/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(+0x33b6d83)[0x7f18fb1b6d83]
/lib/x86_64-linux-gnu/libc.so.6(+0x3c050)[0x7f18f7c5b050]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm9MemorySSA23insertIntoListsForBlockEPNS_12MemoryAccessEPKNS_10BasicBlockENS0_14InsertionPlaceE+0x18d)[0x7f18f619341d]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x6f50465)[0x7f18f6d50465]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x63d72d1)[0x7f18f61d72d1]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x63d6be8)[0x7f18f61d6be8]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm11PassManagerINS_4LoopENS_15AnalysisManagerIS1_JRNS_27LoopStandardAnalysisResultsEEEEJS4_RNS_10LPMUpdaterEEE24runWithoutLoopNestPassesERS1_RS5_S4_S7_+0x4ac)[0x7f18f5f5e1c2]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x615dc2e)[0x7f18f5f5dc2e]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm25FunctionToLoopPassAdaptor3runERNS_8FunctionERNS_15AnalysisManagerIS1_JEEE+0x60b)[0x7f18f5e1ed0b]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x601e6df)[0x7f18f5e1e6df]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm11PassManagerINS_8FunctionENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0xb87)[0x7f18f5e1d061]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm26CGSCCToFunctionPassAdaptor3runERNS_13LazyCallGraph3SCCERNS_15AnalysisManagerIS2_JRS1_EEES5_RNS_17CGSCCUpdateResultE+0x36a)[0x7f18f6041b2a]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x62417b5)[0x7f18f60417b5]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm11PassManagerINS_13LazyCallGraph3SCCENS_15AnalysisManagerIS2_JRS1_EEEJS4_RNS_17CGSCCUpdateResultEEE3runERS2_RS5_S4_S7_+0x94f)[0x7f18f604092d]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm21DevirtSCCRepeatedPass3runERNS_13LazyCallGraph3SCCERNS_15AnalysisManagerIS2_JRS1_EEES5_RNS_17CGSCCUpdateResultE+0x183)[0x7f18f603f4c3]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm33ModuleToPostOrderCGSCCPassAdaptor3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0xa03)[0x7f18f603e115]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x623d70d)[0x7f18f603d70d]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm11PassManagerINS_6ModuleENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0x229)[0x7f18f6585ea9]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm24ModuleInlinerWrapperPass3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0x1a1)[0x7f18f6587761]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(+0x67875af)[0x7f18f65875af]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/libLLVM.so.19.1-rust-1.82.0-stable(_ZN4llvm11PassManagerINS_6ModuleENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0x229)[0x7f18f6585ea9]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(LLVMRustOptimize+0x84c)[0x7f18fd5b6098]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(+0x57b7f2f)[0x7f18fd5b7f2f]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(_RNvXs1_Cs1oxnbOlTNyI_18rustc_codegen_llvmNtB5_18LlvmCodegenBackendNtNtNtCs6rvTwnzI2jg_17rustc_codegen_ssa6traits5write19WriteBackendMethods8optimize+0x135)[0x7f18fd67f6f5]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(+0x5878c58)[0x7f18fd678c58]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(+0x5878821)[0x7f18fd678821]
/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/lib/librustc_driver-2d2db9d3929202cf.so(+0x5877d2b)[0x7f18fd677d2b]
/lib/x86_64-linux-gnu/libc.so.6(+0x891c4)[0x7f18f7ca81c4]
/lib/x86_64-linux-gnu/libc.so.6(__clone+0x40)[0x7f18f7d27ac0]

note: we would appreciate a report at https://github.com/rust-lang/rust
help: you can increase rustc's stack size by setting RUST_MIN_STACK=16777216
note: backtrace dumped due to SIGSEGV! resuming signal
error: could not compile `rustc-sigsegv` (bin "rustc-sigsegv")

Caused by:
  process didn't exit successfully: `/usr/local/rustup/toolchains/1.82.0-x86_64-unknown-linux-gnu/bin/rustc --crate-name rustc_sigsegv --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C opt-level=3 -C embed-bitcode=no --check-cfg 'cfg(docsrs)' --check-cfg 'cfg(feature, values())' -C metadata=aba743abba83be16 -C extra-filename=-aba743abba83be16 --out-dir /target/release/deps -C strip=debuginfo -L dependency=/target/release/deps --extern anyhow=/target/release/deps/libanyhow-863377357f01da5a.rlib --extern clap=/target/release/deps/libclap-6f313dd98669d063.rlib` (signal: 11, SIGSEGV: invalid memory reference)

[bjorn3]

This looks like it is either an LLVM bug or rustc producing invalid LLVM IR.

[dianqk]

Reduced: https://llvm.godbolt.org/z/hbTEMc7qs

[dianqk]

Upstream issue: llvm/llvm-project#116809
🌕💤️

[saethlin]

I swear I posted this comment already. Huh.

I noted that a lot of existing SIGSEGV issues were marked as C-defective-hardware, so I replicated the issue on three different machines to try and rule that out.

The signature of defective hardware is getting different behavior build-to-build; sometimes the build succeeds, and when it crashes you get various different backtraces. If you always get exactly the same behavior, high chance it's a compiler bug of some sort.