Cargo error after installing last nightly on aarch64-unknown-linux-musl (Alpine 3.15 based docker container)

[yogh333]

Problem

After upgrading to the last nightly rustup update nightly, I have an error when trying to use cargo:

cargo +nightly
Error relocating /opt/rustup/toolchains/nightly-aarch64-unknown-linux-musl/bin/cargo: pthread_getname_np: symbol not found

Same issue with rustc

Steps

No response

Possible Solution(s)

No response

Notes

No response

Version

No response

[weihanglo]

Please include the version of the toolchain via cargo -vV, and also the steps to reproduce. Thank you.

[yogh333]

cargo -vV
cargo 1.75.0 (1d8b05cdd 2023-11-20)
release: 1.75.0
commit-hash: 1d8b05cdd1287c64467306cf3ca2c8ac60c11eb0
commit-date: 2023-11-20
host: aarch64-unknown-linux-musl
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.4.0-DEV (sys:0.4.68+curl-8.4.0 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Alpine Linux 3.15.11 [64-bit]

Steps to reproduce:

• rustup update nightly
• cargo +nightly -vV => Error relocating /opt/rustup/toolchains/nightly-aarch64-unknown-linux-musl/bin/cargo: pthread_getname_np: symbol not found

[ehuss]

Transferred to rust-lang/rust, since this was a change via #121666.

cc @ChrisDenton

[ehuss]

I believe the issue is that pthread_getname_np was added in musl 1.2.3, but that version of Alpine has musl 1.2.2.

[ChrisDenton]

Hm I thought our minimum support was for 1.2.3? E.g. https://github.com/rust-lang/rust/blob/7606c13961ddc1174b70638e934df0439b7dc515/src/ci/docker/scripts/musl-toolchain.sh#L48C53-L48C58

Edit: Ah rust-lang/compiler-team#572

[ehuss]

Ah. Yea, the minimum requirements were updated to musl 1.2.3 in Rust 1.71.

Should the minimum version be specified in https://doc.rust-lang.org/nightly/rustc/platform-support.html? cc @wesleywiser if you had a reason to not document that?

[wesleywiser]

@ehuss No reason not to document it, the platform support doc just slipped my mind when I did the change. I've opened #121994 to document it.

[ehuss]

Unless someone knows of a way for the binary to produce a better error message when a too-old environment is used for the -linux-musl target, I would suggest this issue be closed as resolved. I'm not familiar with musl or how to handle versioning with its .so.

[wesleywiser]

I'm not aware of an option here either so I'm going to close this. The proper solution is probably to have musl's loader detect the situation and offer a better error message.

[rochdev]

Just want to make sure I properly understand the resolution of this thread since I'm getting the same error. Does this mean that musl 1.1 and earlier 1.2.x versions are no longer supported by Rust and it's now expected that it's not possible to build on these versions?

[wesleywiser]

Hi @rochdev, Alpine uses a different numbering scheme than musl does. You are correct that Rust expects at least musl 1.2.3 to operate which is available in Alpine 3.16 and newer (Alpine 3.15 and older are EOL).

[kennytm]

if you don't need to rely on the default thread name and don't want to edit libstd you can put this somewhere in your code to stub out the missing function.

use std::{ffi::{c_int, c_char}, os::unix::thread::RawPthread};
#[no_mangle]
pub extern "C" fn pthread_getname_np(_thread: RawPthread, _name: *mut c_char, _len: usize) -> c_int {
    13 // EACCES
}

---

BTW if we are serious about dropping musl 1.2.2 support this cfg can also be changed:

rust/library/std/src/thread/tests.rs

Lines 41 to 42 in 3cbb932

	// Note: musl didn't add pthread_getname_np until 1.2.3
	all(target_os = "linux", target_env = "gnu"),