rustc on NixOS produces SIGBUS: access to undefined memory

[Noah765]

I published a reproducible example at https://github.com/Noah765/rust-bug. Adding the dependency tokio with the macros feature enabled results in the error. Interestingly, although the output states that the compilation of quote failed, compilation succeeds when tokio is replaced with quote.

Meta

I am using NixOS and installed Rust using rustup. I added a flake to the example repository that provides a devshell with the rustup version I used. The issue persists when using nightly, as well as when installing cargo from nixpkgs instead of using rustup.

rustc --version --verbose:

rustc 1.87.0 (17067e9ac 2025-05-09)
binary: rustc
commit-hash: 17067e9ac6d7ecb70e50f92c1944e545188d2359
commit-date: 2025-05-09
host: x86_64-unknown-linux-gnu
release: 1.87.0
LLVM version: 20.1.1

Backtrace

   Compiling proc-macro2 v1.0.95
   Compiling unicode-ident v1.0.18
   Compiling pin-project-lite v0.2.16
   Compiling quote v1.0.40
   Compiling syn v2.0.104
error: rustc interrupted by SIGBUS, printing backtrace

/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x39177df) [0x7ffff3f177df]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x419c0) [0x7ffff02419c0]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x17f081) [0x7ffff037f081]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvMs2_NtCs2kjfqayDDYo_6object5writeNtB5_7Section11append_data+0x108) [0x7ffff6750d5e]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x6150ea4) [0x7ffff6750ea4]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5fcbe3f) [0x7ffff65cbe3f]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvNtNtCs2ZezlIswSFH_17rustc_codegen_ssa4back4link11link_binary+0x586) [0x7ffff62e2da2]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvMNtCs6PtJWl2j4pF_15rustc_interface7queriesNtB2_6Linker4link+0x455) [0x7ffff672dc31]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x6124039) [0x7ffff6724039]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RINvNtNtCseJswNlh1fGO_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCs6PtJWl2j4pF_15rustc_interface4util26run_in_thread_with_globalsNCINvB1e_31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCsj20AIVrSq7d_17rustc_driver_impl12run_compiler0Es_0uE0uE00uEB3C_+0x148) [0x7ffff6564f08]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5f657f4) [0x7ffff65657f4]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5f66bf7) [0x7ffff6566bf7]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x9af08) [0x7ffff029af08]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x1230ac) [0x7ffff03230ac]

note: we would appreciate a report at https://github.com/rust-lang/rust
error: could not compile `quote` (lib)

Caused by:
  process didn't exit successfully: `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name quote --edition=2018 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/quote-1.0.40/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "proc-macro"))' -C metadata=f3ea2777483e0cff -C extra-filename=-633ca24bad203381 --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --extern proc_macro2=/home/noah/projects/rust-bug/target/debug/deps/libproc_macro2-7d83e77cb55998ce.rmeta --cap-lints allow` (signal: 7, SIGBUS: access to undefined memory)
warning: build failed, waiting for other jobs to finish...

[Noratrieb]

That's strange, I've successfully used the rustup package on NixOS for a long time. Is this a recent regression? Did you have old build artifacts around or did you cargo clean?

[Noah765]

The strange thing is that I've been using the cargo package from Nixpkgs for a while now and have never encountered this issue. I tried multiple versions of Nixpkgs with rustup and cargo. For each test, I deleted the ~/.cargo and ~/.rustup folders before running cargo clean; cargo build inside the repository above. I had to change the edition in Cargo.toml for older versions, but that shouldn't matter. I got the following results:

May 31, 2024 (24.05): cargo 1.77.1 works
Mar 7, 2025 (24.11): cargo 1.82.0 doesn't work

The cargo package of the master branch of nixpkgs:
May 31, 2024 (0de0253ffbd88526af1b15ab281bd4cc17ef0d4f): 1.77.1 works
Jun 1, 2024 (11967e5d840372f8d6828d0474c49b1732cc2af7): 1.77.1 works
Jun 7, 2024 (121ba21838380d29d3580394413d834c28a73b9f): 1.77.1 works
Jun 11, 2024 (93908113cbe1c10b685f9bc81d1ec3718342edd2): 1.77.1 works
Jun 12, 2024 (e802a5faf4da9315059b3cba4ddbfb90a0e751c0): 1.77.1 works
Jun 12, 2024 (447b3eccaf30d7a74e61ebd465a5d88897368c31): 1.77.1 works
Jun 12, 2024 (edaab670f8eaa9561504df5963974511e8d93148): 1.77.1 works
Jun 12, 2024 (6355ddc8e8e44796c66bcc2303414e8982ac01cf): 1.77.1 works
Jun 12, 2024 (665f3f694bfc6c2f3a95a98b1abf71d2961879bb): 1.77.1 works
Jun 12, 2024 (c6e1d0bf0fe6369e45e345f32f4d6b8b961679b3): 1.77.1 works
Jun 12, 2024 (715b4dadb6a011ddd594710b5e6d4ed429542d5b): 1.77.1 works

BREAKING COMMIT: 83b4a2178fb79a24a27f53e72f28b11ba27f2835: 1.78.0 doesn't work

Jun 12, 2024 (2ff09eadf5a41ffd4c1054c606a9455f974753a0): 1.78.0 doesn't work
Jun 12, 2024 (3d968636859bf1bd8df0868f4227f71393cd12a5): 1.78.0 doesn't work
Jun 13, 2024 (efef8be03823372fa51a7f7e9ee5cbd25d0b6f69): 1.78.0 doesn't work
Jun 15, 2024 (b339a999966f5b7666f4f808f3a3600e69e74240) 1.78.0 doesn't work
Jul 1, 2024 (540b06943397e3ff6743236cb5a639e76ddae731): 1.78.0 doesn't work
Oct 31, 2024 (7eee04bbcccf450adab2a88e386393677b558703): 1.82.0 doesn't work

rustup on 24.05: cargo 1.77.1 doesn't work
rustup on 24.05: cargo 1.82.0 doesn't work
rustup on 24.11: cargo 1.77.1 doesn't work
rustup on 24.11: cargo 1.82.0 doesn't work

'Doesn't work' means that `cargo build` failed with a 'SIGBUS: access to undefined memory' error. This failure isn't consistent, though, as running `cargo clean; cargo build` succeeds on rare occasions.

In short, the cargo versions provided by rustup don't work on my machine. This occurs even when using an older version of rustup or cargo. The commit nixpkgs 83b4a2178fb79a24a27f53e72f28b11ba27f2835 seems to upgrade cargo from version 1.77.1 to version 1.78.0, but it doesn't seem to be related at all. Cargo works fine before this commit but almost always produces a SIGBUS: access to undefined memory error when running the above commands with any cargo version after the commit. I have no idea what's going on. Could you reproduce the Cargo version change at that commit?

If that doesn't lead to anything, I can try bisecting my NixOS config. I have set up impermanence on my system, so rogue files shouldn't be the issue.

[Noah765]

I determined that NixOS/nixpkgs@a45a73a is the cause of this error on my machine. Both the cargo package from nixpkgs and the cargo package installed by rustup from nixpkgs fail with the SIGBUS: access to undefined memory error when building my NixOS system with this or newer versions of nixpkgs. However, they succeed with older versions of nixpkgs. I don't have anything Rust-specific configured, so this might be enough to reproduce the error?

[workingjubilee]

@Noratrieb it seems nixpkgs doesn't set LLVM_UNREACHABLE_OPTIMIZE=OFF for its LLVM builds, is that causing a problem?

[Noratrieb]

There seems to be some confusion of packages. The rustup package merely provides the rustup binary, which downloads cargo/rustc and all other assets from static.rust-lang.org (and then patches them to make them work on NixOS). The cargo package is instead built natively using nix.

I cloned your repo, entered your devshell and ran cargo build but I was not able to reproduce any problem, I compiled it 10 times and it worked.
Is your backtrace consistent between executions or does it vary? Also, can you show cargo build --verbose to show what exactly is executed?

Programs SIGBUSing in certain cases on NixOS is certainly nothing new, but this failure seems very strange to me.

@workingjubilee I see no reason why this random LLVM config is supposed to cause the problem, at worst it makes the crash error message more obscure.

[workingjubilee]

@Noratrieb I only think it would reveal the actual bug, that's all!

[Noah765]

As I mentioned earlier, I only encountered this error after upgrading my NixOS config's nixpkgs to NixOS/nixpkgs@a45a73a or higher. Therefore, something in my environment that cargo or rustc depend on must have changed. I don't get the error when using any nixpkgs version prior to that.

There seems to be some confusion of packages. The rustup package merely provides the rustup binary, which downloads cargo/rustc and all other assets from static.rust-lang.org (and then patches them to make them work on NixOS). The cargo package is instead built natively using nix.

I mentioned the cargo package from nixpkgs to highlight the different behaviors of various versions and installation procedures (i.e., using the cargo package versus installing cargo using the rustup package). Using cargo installed via the rustup package from nixpkgs in this error-inducing environment seems to always result in an error message similar to the one above, even when using older versions of the rustup package (i.e., the package as described by older versions of nixpkgs. I haven't confirmed whether a different derivation is actually produced) or installing older versions of cargo using the same rustup derivation. Interestingly, using the same versions of cargo but packaged with Nix instead of being installed with rustup results in different behavior. Using the cargo package provided by the nixpkgs release 24.05, I don't get any compilation errors. However, I still get the same error for newer derivations of cargo as provided by nixpkgs.

Is your backtrace consistent between executions or does it vary? Also, can you show cargo build --verbose to show what exactly is executed?

The error message seems to be consistent between executions. However, the backtraces differ slightly between different versions of cargo. Below is the output of cargo clean; cargo build --verbose, with cargo installed using rustup as provided by the devshell from https://github.com/Noah765/rust-bug:

Error message

info: syncing channel updates for 'stable-x86_64-unknown-linux-gnu'
info: latest update on 2025-05-15, rust version 1.87.0 (17067e9ac 2025-05-09)
info: downloading component 'cargo'
info: downloading component 'clippy'
info: downloading component 'rust-docs'
info: downloading component 'rust-std'
info: downloading component 'rustc'
info: downloading component 'rustfmt'
info: installing component 'cargo'
info: installing component 'clippy'
info: installing component 'rust-docs'
info: installing component 'rust-std'
info: installing component 'rustc'
info: installing component 'rustfmt'
     Removed 81 files, 21.1MiB total
    Updating crates.io index
  Downloaded tokio-macros v2.5.0
  Downloaded proc-macro2 v1.0.95
  Downloaded pin-project-lite v0.2.16
  Downloaded quote v1.0.40
  Downloaded unicode-ident v1.0.18
  Downloaded syn v2.0.104
  Downloaded tokio v1.45.1
  Downloaded 7 crates (1.2MiB) in 0.33s
   Compiling proc-macro2 v1.0.95
   Compiling unicode-ident v1.0.18
   Compiling pin-project-lite v0.2.16
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name unicode_ident --edition=2018 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/unicode-ident-1.0.18/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=052ba14cf376a63a -C extra-filename=-43c3b454bec3b76f --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --cap-lints allow`
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name pin_project_lite --edition=2018 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/pin-project-lite-0.2.16/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --warn=unreachable_pub --warn=unexpected_cfgs '--warn=clippy::undocumented_unsafe_blocks' '--warn=clippy::transmute_undefined_repr' '--warn=clippy::trailing_empty_array' --warn=single_use_lifetimes --warn=rust_2018_idioms '--warn=clippy::pedantic' --warn=non_ascii_idents '--warn=clippy::inline_asm_x86_att_syntax' --warn=improper_ctypes_definitions --warn=improper_ctypes --warn=deprecated_safe '--warn=clippy::default_union_representation' '--warn=clippy::as_underscore' '--warn=clippy::as_ptr_cast_mut' '--warn=clippy::all' '--allow=clippy::unreadable_literal' '--allow=clippy::type_complexity' '--allow=clippy::too_many_lines' '--allow=clippy::too_many_arguments' '--allow=clippy::struct_field_names' '--allow=clippy::struct_excessive_bools' '--allow=clippy::single_match_else' '--allow=clippy::single_match' '--allow=clippy::similar_names' '--allow=clippy::range_plus_one' '--allow=clippy::nonminimal_bool' '--allow=clippy::naive_bytecount' '--allow=clippy::module_name_repetitions' '--allow=clippy::missing_errors_doc' '--allow=clippy::manual_range_contains' '--allow=clippy::manual_assert' '--allow=clippy::lint_groups_priority' '--allow=clippy::incompatible_msrv' '--allow=clippy::float_cmp' '--allow=clippy::doc_markdown' '--allow=clippy::declare_interior_mutable_const' '--allow=clippy::cast_lossless' '--allow=clippy::borrow_as_ptr' '--allow=clippy::bool_assert_comparison' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=993972bacc6798ae -C extra-filename=-12250a02a17ca230 --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --cap-lints allow`
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name build_script_build --edition=2021 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.95/build.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type bin --emit=dep-info,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "nightly", "proc-macro", "span-locations"))' -C metadata=e1755b0d7d0809a5 -C extra-filename=-3c7cf2cb897bcc27 --out-dir /home/noah/projects/rust-bug/target/debug/build/proc-macro2-3c7cf2cb897bcc27 -L dependency=/home/noah/projects/rust-bug/target/debug/deps --cap-lints allow`
     Running `/home/noah/projects/rust-bug/target/debug/build/proc-macro2-3c7cf2cb897bcc27/build-script-build`
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name proc_macro2 --edition=2021 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.95/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "nightly", "proc-macro", "span-locations"))' -C metadata=063a7131fddd8a77 -C extra-filename=-7d83e77cb55998ce --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --extern unicode_ident=/home/noah/projects/rust-bug/target/debug/deps/libunicode_ident-43c3b454bec3b76f.rmeta --cap-lints allow --cfg wrap_proc_macro --check-cfg 'cfg(fuzzing)' --check-cfg 'cfg(no_is_available)' --check-cfg 'cfg(no_literal_byte_character)' --check-cfg 'cfg(no_literal_c_string)' --check-cfg 'cfg(no_source_text)' --check-cfg 'cfg(proc_macro_span)' --check-cfg 'cfg(procmacro2_backtrace)' --check-cfg 'cfg(procmacro2_nightly_testing)' --check-cfg 'cfg(procmacro2_semver_exempt)' --check-cfg 'cfg(randomize_layout)' --check-cfg 'cfg(span_locations)' --check-cfg 'cfg(super_unstable)' --check-cfg 'cfg(wrap_proc_macro)'`
   Compiling quote v1.0.40
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name quote --edition=2018 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/quote-1.0.40/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "proc-macro"))' -C metadata=f3ea2777483e0cff -C extra-filename=-633ca24bad203381 --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --extern proc_macro2=/home/noah/projects/rust-bug/target/debug/deps/libproc_macro2-7d83e77cb55998ce.rmeta --cap-lints allow`
   Compiling syn v2.0.104
     Running `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name syn --edition=2021 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/syn-2.0.104/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="full"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("clone-impls", "default", "derive", "extra-traits", "fold", "full", "parsing", "printing", "proc-macro", "test", "visit", "visit-mut"))' -C metadata=0b9077a3128b7a2a -C extra-filename=-f9d4c30ac5e40796 --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --extern proc_macro2=/home/noah/projects/rust-bug/target/debug/deps/libproc_macro2-7d83e77cb55998ce.rmeta --extern quote=/home/noah/projects/rust-bug/target/debug/deps/libquote-633ca24bad203381.rmeta --extern unicode_ident=/home/noah/projects/rust-bug/target/debug/deps/libunicode_ident-43c3b454bec3b76f.rmeta --cap-lints allow`
error: rustc interrupted by SIGBUS, printing backtrace

/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x39177df) [0x7f47a5f177df]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x419c0) [0x7f47a22419c0]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x17f081) [0x7f47a237f081]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvMs2_NtCs2kjfqayDDYo_6object5writeNtB5_7Section11append_data+0x108) [0x7f47a8750d5e]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x6150ea4) [0x7f47a8750ea4]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5fcbe3f) [0x7f47a85cbe3f]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvNtNtCs2ZezlIswSFH_17rustc_codegen_ssa4back4link11link_binary+0x586) [0x7f47a82e2da2]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RNvMNtCs6PtJWl2j4pF_15rustc_interface7queriesNtB2_6Linker4link+0x455) [0x7f47a872dc31]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x6124039) [0x7f47a8724039]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(_RINvNtNtCseJswNlh1fGO_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCs6PtJWl2j4pF_15rustc_interface4util26run_in_thread_with_globalsNCINvB1e_31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCsj20AIVrSq7d_17rustc_driver_impl12run_compiler0Es_0uE0uE00uEB3C_+0x148) [0x7f47a8564f08]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5f657f4) [0x7f47a85657f4]
/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/librustc_driver-9c23edfdcf82221e.so(+0x5f66bf7) [0x7f47a8566bf7]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x9af08) [0x7f47a229af08]
/nix/store/q4wq65gl3r8fy746v9bbwgx4gzn0r2kl-glibc-2.40-66/lib/libc.so.6(+0x1230ac) [0x7f47a23230ac]

note: we would appreciate a report at https://github.com/rust-lang/rust
error: could not compile `quote` (lib)

Caused by:
  process didn't exit successfully: `/home/noah/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustc --crate-name quote --edition=2018 /home/noah/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/quote-1.0.40/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=238 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no --cfg 'feature="default"' --cfg 'feature="proc-macro"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("default", "proc-macro"))' -C metadata=f3ea2777483e0cff -C extra-filename=-633ca24bad203381 --out-dir /home/noah/projects/rust-bug/target/debug/deps -L dependency=/home/noah/projects/rust-bug/target/debug/deps --extern proc_macro2=/home/noah/projects/rust-bug/target/debug/deps/libproc_macro2-7d83e77cb55998ce.rmeta --cap-lints allow` (signal: 7, SIGBUS: access to undefined memory)
warning: build failed, waiting for other jobs to finish...

---

I hid my previous comments because my attempt to bisect the issue was flawed and didn't identify the commit that caused the error. Currently, I am attempting to bisect the commit that changed my environment in such a way as to cause this error, in hopes that it will be insightful. I will provide my results once I am done.