error-chain segfault when using causes via libunwind

[clux]

Program received signal SIGSEGV, Segmentation fault.
0x0000000000bff9d3 in libunwind::LocalAddressSpace::get32(unsigned long) ()
(gdb) bt
#0  0x0000000000bff9d3 in libunwind::LocalAddressSpace::get32(unsigned long) ()
#1  0x0000000000c02c80 in libunwind::CFI_Parser<libunwind::LocalAddressSpace>::findFDE(libunwind::LocalAddressSpace&, unsigned long, unsigned long, unsigned int, unsigned long, libunwind::CFI_Parser<libunwind::LocalAddressSpace>::FDE_Info*, libunwind::CFI_Parser<libunwind::LocalAddressSpace>::CIE_Info*) ()
#2  0x0000000000c02417 in libunwind::UnwindCursor<libunwind::LocalAddressSpace, libunwind::Registers_x86_64>::getInfoFromDwarfSection(unsigned long, libunwind::UnwindInfoSections const&, unsigned int) ()
#3  0x0000000000c01e17 in libunwind::UnwindCursor<libunwind::LocalAddressSpace, libunwind::Registers_x86_64>::setInfoBasedOnIPRegister(bool) ()
#4  0x0000000000c01bd9 in libunwind::UnwindCursor<libunwind::LocalAddressSpace, libunwind::Registers_x86_64>::step() ()
#5  0x0000000000c00d6d in unw_step ()
#6  0x0000000000bfefff in _Unwind_Backtrace ()
#7  0x0000000000b5684d in backtrace::backtrace::libunwind::trace::hd633fbf58699793f (cb=...)
    at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/libunwind.rs:53
#8  backtrace::backtrace::trace::hf547bd4c20bd8958 (cb=...) at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
#9  0x0000000000b55803 in backtrace::capture::Backtrace::new_unresolved::hb79408d21b35173a () at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
#10 backtrace::capture::Backtrace::new::ha127780e86ae8348 () at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:63
#11 _$LT$backtrace..capture..Backtrace$u20$as$u20$core..default..Default$GT$::default::hc59e5c652a626061 ()
    at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:235
#12 0x0000000000b55879 in backtrace::capture::Backtrace::new::ha127780e86ae8348 ()
#13 0x000000000070bf1d in error_chain::make_backtrace::h3de17587d40dd8d9 () at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.11.0/src/lib.rs:616
#14 0x000000000070bfa5 in _$LT$error_chain..State$u20$as$u20$core..default..Default$GT$::default::h83acd38a3fbdd55d ()
    at /root/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.11.0/src/lib.rs:710
#15 0x000000000053842f in myapp::Error::from_kind::hf7853880c89cea62 (kind=...) at <impl_error_chain_processed macros>:53
#16 _$LT$myapp..Error$u20$as$u20$core..convert..From$LT$alloc..string..String$GT$$GT$::from::h4fbf2a56c4646783 (s=...) at <impl_error_chain_processed macros>:102
#17 _$LT$T$u20$as$u20$core..convert..Into$LT$U$GT$$GT$::into::h583c99ca38db9c0f (self=...) at /checkout/src/libcore/convert.rs:396
#21 0x000000000040860b in myapp::main::hf2459d8155fbc2b7 () at src/main.rs:256
#22 0x0000000000401043 in std::rt::lang_start::_$u7b$$u7b$closure$u7d$$u7d$::h8404db9011a8df06 () at /checkout/src/libstd/rt.rs:74
#23 0x0000000000bee4d3 in std::rt::lang_start_internal::_$u7b$$u7b$closure$u7d$$u7d$::hb94c47f3eedfaa55 () at libstd/rt.rs:59
#24 std::panicking::try::do_call::h9a1cf6ef7a2bbed3 () at libstd/panicking.rs:310
#25 0x0000000000bfd3fa in __rust_maybe_catch_panic () at libpanic_unwind/lib.rs:105
#26 0x0000000000be0e2e in std::panicking::try::hb22e57d7731fdf53 () at libstd/panicking.rs:289
#27 std::panic::catch_unwind::h813102482f9fd064 () at libstd/panic.rs:392
#28 std::rt::lang_start_internal::h45c8433e0c8ada66 () at libstd/rt.rs:58

Noticed on old kernels (CircleCI host) only, works fine on local machine using the musl compiled executable, but on ubuntu 14.04 in circle, non-trivial chain_err iteration cause segfaults.

Upstream issue: rust-lang/rust#47551

[clux]

Temporary error handling work-around that (though there's probably a better thing to check for than CIRCLECI):

fn result_exit<T>(name: &str, x: Result<T>) {
    use std::env;
    let _ = x.map_err(|e| {
        error!("{} error: {}", name, e);
        // print causes of error if present
        if let Ok(_) = env::var("CIRCLECI") {
            // only print debug implementation rather than unwinding
            // this prints the firsts chained cause (better than not doing anything)
            warn!("{:?}", e);
        } else {
            // normal case - assume libunwind works
            for e in e.iter().skip(1) {
                warn!("caused by: {}", e);
            }
        }
        process::exit(1);
    });
    process::exit(0);
}

Works fine for me on CircleCI, and you typically only iterate over error causes once.

[clux]

Going to close this for a number of reasons:

• not heart of anyone else having a similar problem
• last we hit this we were on ubuntu 14.04
• no one is really using error-chain much anymore