Steps to reproduce

I’ve managed to work my code down to this minimal example:

(Clarification edit: As the title indicates, I have only encountered this when trying to build/test against musl libc; the same programs build fine when targetting glibc.)

rustup target install x86_64-unknown-linux-musl  # Or however you need to do it for your setup

cd /tmp
cargo new test-tarpaulin
cd test-tarpaulin

cat <<EOF >src/main.rs
fn a()  {
    if unsafe { libc::getpid() } < 0 {
        panic!("{}", std::io::Error::last_os_error());
    }
}
EOF
echo 'libc = "0.2"' >>Cargo.toml

cargo tarpaulin --target=x86_64-unknown-linux-musl --verbose

What should happen

tarpaulin builds the target and runs successfully. (It worked with tarpaulin v0.16.0.)

What actually happens

tarpaulin fails with a message about a segfault.

Nov 11 16:45:29.104 DEBUG cargo_tarpaulin: set up logging
Nov 11 16:45:29.104  INFO cargo_tarpaulin::config: Creating config
Nov 11 16:45:29.118  INFO cargo_tarpaulin: Running Tarpaulin
Nov 11 16:45:29.118  INFO cargo_tarpaulin: Building project
   Compiling bitflags v1.2.1
   Compiling libc v0.2.80
   Compiling test-tarpaulin v0.1.0 (/tmp/test-tarpaulin)
    Finished test [unoptimized + debuginfo] target(s) in 1.08s
Nov 11 16:45:30.257  INFO cargo_tarpaulin: Launching test
Nov 11 16:45:30.257  INFO cargo_tarpaulin: running /tmp/test-tarpaulin/target/x86_64-unknown-linux-musl/debug/deps/test_tarpaulin-86c594765747da0f
Nov 11 16:45:30.534 ERROR cargo_tarpaulin: Failed to get test coverage! Error: Failed to run tests: A segfault occurred while executing tests
Error: "Failed to get test coverage! Error: Failed to run tests: A segfault occurred while executing tests

I’m not familiar with tarpaulin’s internals (not by a long shot 😃, so I can’t debug this any further.

Environment

I’ve been able to reproduce this on Arch Linux, Void Linux, and Ubuntu (all three had rustc 1.47.0 and were running either the latest kernel from the repos or only a few revisions behind).

Potential cause

It looks like this regression was caused (at least, most directly) by #613. RUSTFLAGS='-C relocation-model=dynamic-no-pic' cargo tarpaulin --target=x86_64-unknown-linux-musl --verbose builds with no problems.