x86_64-unknown-linux-musl binaries SIGSEGV during early initialization

[nagisa]

Minimized reproducer

fn main() {}

// $ rustc --target=x86_64-unknown-linux-musl test.rs
// $ ./test
// fish: “./test” terminated by signal SIGSEGV (Address boundary error)

Stack trace:

(gdb) bt
#0  0x0000555555558193 in _start_c ()
#1  0x00007fffffffc6b9 in ?? ()
#2  0x00000000178bfbff in ?? ()
#3  0x0000000000000064 in ?? ()
#4  0x0000000000000000 in ?? ()

The faulting instruction is this:

0x0000555555558193 <+291>:   mov    0x8(%rdx),%rsi

The register value is not obviously wrong (i.e. its not 0 or something like that), so could be a buffer overrun of some sort.

rustc 1.45.0 (5c1f21c 2020-07-13) works.
rustc 1.46.0-beta.2 (6f95990 2020-07-23) fails.
rustc 1.47.0-nightly (5ef299e 2020-07-24) fails.

[cuviper]

It works for me on all of those same versions.

Maybe it's a system toolchain issue? I'm using Fedora 32, and I don't have any system musl packages installed, so it will be purely using rust's version of the musl CRT objects.

[cuviper]

Maybe #70740 or #73089? Both have reached beta but not yet stable.

[nagisa]

Marking as O-NixOS then where this was reproduced.

[nagisa]

Disabling pie helps:

$ rustc --version; and rustc --target=x86_64-unknown-linux-musl test.rs -C relocation-model=static; and ./test
rustc 1.46.0-beta.2 (6f959902b 2020-07-23)
$ echo $status
0

[nagisa]

It looks like the issue is coming from the fact that on NixOS cc wraps gcc to add the following arguments

  -Wl\,-dynamic-linker
  -Wl\,/nix/store/jx19wa4xlh9n4324xdl9rjnykd19mmq3-glibc-2.30/lib/ld-linux-x86-64.so.2

If the wrapper is not utilized, or these arguments are removed, the binary runs correctly. Conversely if its run with the interpreter directly it also faults even if the DT_INTERP is not set:

/nix/store/jx19wa4xlh9n4324xdl9rjnykd19mmq3-glibc-2.30/lib/ld-linux-x86-64.so.2 ./test
fish: “/nix/store/jx19wa4xlh9n4324xdl9…” terminated by signal SIGSEGV (Address boundary error)

Possibly not a rustc bug either way.

[LeSeulArtichaut]

Possibly not a rustc bug either way.

@nagisa what do you think would be the next steps to resolve this?

[nagisa]

It likely deserves an issue report to both nixos and musl upstreams. I’m going to do it as time permits. Then this can be closed.