Mapping libxul.so on Linux panics in xmas_elf::ElfFile::get_string due to bad slice about addr2line

[philipc]

For a smaller test case, compile the following using g++ -g -Os -std=gnu++11 -fno-exceptions

#include <iostream>
struct Foo { Foo() { std::cout << "Foo\n"; } };
typedef struct { Foo foo; } Bar;
int main() { new Bar(); }

The constructor for Bar is missing a name in the DWARF. Sometimes the compiler gives it a name, but not with those specific compilation options. Seems like a compiler bug? We should still handle it by ignoring that subroutine, instead of raising an error.

[fitzgen]

We're in the process of moving to goblin for object file needs -- will need STR + test case to see if this panic still reproduces once we've moved this crate over as well.

Thanks @mstange !

[mstange]

I've experimentally updated the object dependency in addr2line from 0.1.0 to 0.3.0, and now it's no longer panicking, but the mapping returns an error:

   Compiling addr2line v0.3.0 (file:///home/mstange/code/addr2line)
   Compiling addr2line-libxul v0.1.0 (file:///home/mstange/code/addr2line-libxul)
    Finished dev [unoptimized + debuginfo] target(s) in 5.66 secs
     Running `target/debug/addr2line-libxul`
thread 'main' panicked at 'Mapping libxul.so failed: Error(Msg("failed to analyze debug information"), State { next_error: Some(Error(Msg("encountered invalid compilation unit"), State { next_error: Some(Error(InvalidDebugSymbols(SubroutineMissingName(483643027, 3111142)), State { next_error: None, backtrace: Some(stack backtrace:
   0:     0x5628b7fb0b94 - backtrace::backtrace::libunwind::trace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/libunwind.rs:53
                         - backtrace::backtrace::trace<closure>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/mod.rs:42
   1:     0x5628b7fb0f5f - backtrace::capture::{{impl}}::new
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/capture.rs:64
   2:     0x5628b7fa5b9c - error_chain::make_backtrace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:411
   3:     0x5628b7fa5c5f - error_chain::{{impl}}::default
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:462
   4:     0x5628b7f1336c - addr2line::errors::{{impl}}::from_kind
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:48
   5:     0x5628b7f13659 - addr2line::errors::{{impl}}::from
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:8
   6:     0x5628b7f0aa38 - addr2line::{{impl}}::parse<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:732
   7:     0x5628b7effc95 - addr2line::{{impl}}::new<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:287
   8:     0x5628b7efeeab - addr2line::{{impl}}::symbolicate
                        at /home/mstange/code/addr2line/src/lib.rs:250
   9:     0x5628b7efe8ed - addr2line::{{impl}}::new_inner::{{closure}}::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:229
  10:     0x5628b7ebfa9b - owning_ref::{{impl}}::try_new<alloc::boxed::Box<object::elf::Elf>,alloc::boxed::Box<addr2line::EndianDebugInfo>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  11:     0x5628b7efebd0 - addr2line::{{impl}}::new_inner::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:227
  12:     0x5628b7ebf7bb - owning_ref::{{impl}}::try_new<alloc::boxed::Box<memmap::Mmap>,alloc::boxed::Box<addr2line::MmapDerived>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  13:     0x5628b7efe4e5 - addr2line::{{impl}}::new_inner
                        at /home/mstange/code/addr2line/src/lib.rs:223
  14:     0x5628b7e5f941 - addr2line::{{impl}}::build<&str>
                        at /home/mstange/code/addr2line/src/lib.rs:173
  15:     0x5628b7e5fa17 - addr2line_libxul::main
                        at src/main.rs:4
  16:     0x5628b7fd63dc - panic_unwind::__rust_maybe_catch_panic
                        at /checkout/src/libpanic_unwind/lib.rs:98
  17:     0x5628b7fcfbf4 - std::panicking::try<(),closure>
                        at /checkout/src/libstd/panicking.rs:458
                         - std::panic::catch_unwind<closure,()>
                        at /checkout/src/libstd/panic.rs:361
                         - std::rt::lang_start
                        at /checkout/src/libstd/rt.rs:59
  18:     0x5628b7e5fbd2 - main
  19:     0x7ff6e19ba3f0 - __libc_start_main
  20:     0x5628b7e59409 - _start
  21:                0x0 - <unknown>) })), backtrace: Some(stack backtrace:
   0:     0x5628b7fb0b94 - backtrace::backtrace::libunwind::trace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/libunwind.rs:53
                         - backtrace::backtrace::trace<closure>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/mod.rs:42
   1:     0x5628b7fb0f5f - backtrace::capture::{{impl}}::new
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/capture.rs:64
   2:     0x5628b7fa5b9c - error_chain::make_backtrace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:411
   3:     0x5628b7fa5c5f - error_chain::{{impl}}::default
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:462
   4:     0x5628b7f1336c - addr2line::errors::{{impl}}::from_kind
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:48
   5:     0x5628b7f13659 - addr2line::errors::{{impl}}::from
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:8
   6:     0x5628b7f0aa38 - addr2line::{{impl}}::parse<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:732
   7:     0x5628b7effc95 - addr2line::{{impl}}::new<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:287
   8:     0x5628b7efeeab - addr2line::{{impl}}::symbolicate
                        at /home/mstange/code/addr2line/src/lib.rs:250
   9:     0x5628b7efe8ed - addr2line::{{impl}}::new_inner::{{closure}}::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:229
  10:     0x5628b7ebfa9b - owning_ref::{{impl}}::try_new<alloc::boxed::Box<object::elf::Elf>,alloc::boxed::Box<addr2line::EndianDebugInfo>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  11:     0x5628b7efebd0 - addr2line::{{impl}}::new_inner::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:227
  12:     0x5628b7ebf7bb - owning_ref::{{impl}}::try_new<alloc::boxed::Box<memmap::Mmap>,alloc::boxed::Box<addr2line::MmapDerived>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  13:     0x5628b7efe4e5 - addr2line::{{impl}}::new_inner
                        at /home/mstange/code/addr2line/src/lib.rs:223
  14:     0x5628b7e5f941 - addr2line::{{impl}}::build<&str>
                        at /home/mstange/code/addr2line/src/lib.rs:173
  15:     0x5628b7e5fa17 - addr2line_libxul::main
                        at src/main.rs:4
  16:     0x5628b7fd63dc - panic_unwind::__rust_maybe_catch_panic
                        at /checkout/src/libpanic_unwind/lib.rs:98
  17:     0x5628b7fcfbf4 - std::panicking::try<(),closure>
                        at /checkout/src/libstd/panicking.rs:458
                         - std::panic::catch_unwind<closure,()>
                        at /checkout/src/libstd/panic.rs:361
                         - std::rt::lang_start
                        at /checkout/src/libstd/rt.rs:59
  18:     0x5628b7e5fbd2 - main
  19:     0x7ff6e19ba3f0 - __libc_start_main
  20:     0x5628b7e59409 - _start
  21:                0x0 - <unknown>) })), backtrace: Some(stack backtrace:
   0:     0x5628b7fb0b94 - backtrace::backtrace::libunwind::trace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/libunwind.rs:53
                         - backtrace::backtrace::trace<closure>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/mod.rs:42
   1:     0x5628b7fb0f5f - backtrace::capture::{{impl}}::new
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/capture.rs:64
   2:     0x5628b7fa5b9c - error_chain::make_backtrace
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:411
   3:     0x5628b7fa5c5f - error_chain::{{impl}}::default
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.7.2/src/lib.rs:462
   4:     0x5628b7f1336c - addr2line::errors::{{impl}}::from_kind
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:48
   5:     0x5628b7f13659 - addr2line::errors::{{impl}}::from
                        at /home/mstange/code/addr2line-libxul/<error_chain_processed macros>:8
   6:     0x5628b7f0aa38 - addr2line::{{impl}}::parse<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:732
   7:     0x5628b7effc95 - addr2line::{{impl}}::new<gimli::endianity::LittleEndian>
                        at /home/mstange/code/addr2line/src/lib.rs:287
   8:     0x5628b7efeeab - addr2line::{{impl}}::symbolicate
                        at /home/mstange/code/addr2line/src/lib.rs:250
   9:     0x5628b7efe8ed - addr2line::{{impl}}::new_inner::{{closure}}::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:229
  10:     0x5628b7ebfa9b - owning_ref::{{impl}}::try_new<alloc::boxed::Box<object::elf::Elf>,alloc::boxed::Box<addr2line::EndianDebugInfo>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  11:     0x5628b7efebd0 - addr2line::{{impl}}::new_inner::{{closure}}
                        at /home/mstange/code/addr2line/src/lib.rs:227
  12:     0x5628b7ebf7bb - owning_ref::{{impl}}::try_new<alloc::boxed::Box<memmap::Mmap>,alloc::boxed::Box<addr2line::MmapDerived>,closure,addr2line::errors::Error>
                        at /home/mstange/.cargo/registry/src/github.com-1ecc6299db9ec823/owning_ref-0.2.4/src/lib.rs:475
  13:     0x5628b7efe4e5 - addr2line::{{impl}}::new_inner
                        at /home/mstange/code/addr2line/src/lib.rs:223
  14:     0x5628b7e5f941 - addr2line::{{impl}}::build<&str>
                        at /home/mstange/code/addr2line/src/lib.rs:173
  15:     0x5628b7e5fa17 - addr2line_libxul::main
                        at src/main.rs:4
  16:     0x5628b7fd63dc - panic_unwind::__rust_maybe_catch_panic
                        at /checkout/src/libpanic_unwind/lib.rs:98
  17:     0x5628b7fcfbf4 - std::panicking::try<(),closure>
                        at /checkout/src/libstd/panicking.rs:458
                         - std::panic::catch_unwind<closure,()>
                        at /checkout/src/libstd/panic.rs:361
                         - std::rt::lang_start
                        at /checkout/src/libstd/rt.rs:59
  18:     0x5628b7e5fbd2 - main
  19:     0x7ff6e19ba3f0 - __libc_start_main
  20:     0x5628b7e59409 - _start
  21:                0x0 - <unknown>) })', /checkout/src/libcore/result.rs:860:4
stack backtrace:
   0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
             at /checkout/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::_print
             at /checkout/src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at /checkout/src/libstd/sys_common/backtrace.rs:60
             at /checkout/src/libstd/panicking.rs:380
   3: std::panicking::default_hook
             at /checkout/src/libstd/panicking.rs:396
   4: std::panicking::rust_panic_with_hook
             at /checkout/src/libstd/panicking.rs:611
   5: std::panicking::begin_panic_new
             at /checkout/src/libstd/panicking.rs:553
   6: std::panicking::begin_panic_fmt
             at /checkout/src/libstd/panicking.rs:521
   7: rust_begin_unwind
             at /checkout/src/libstd/panicking.rs:497
   8: core::panicking::panic_fmt
             at /checkout/src/libcore/panicking.rs:92
   9: core::result::unwrap_failed
             at /checkout/src/libcore/macros.rs:31
  10: <core::result::Result<T, E>>::expect
             at /checkout/src/libcore/result.rs:762
  11: addr2line_libxul::main
             at src/main.rs:4
  12: __rust_maybe_catch_panic
             at /checkout/src/libpanic_unwind/lib.rs:98
  13: std::rt::lang_start
             at /checkout/src/libstd/panicking.rs:458
             at /checkout/src/libstd/panic.rs:361
             at /checkout/src/libstd/rt.rs:59
  14: main
  15: __libc_start_main
  16: _start

And that's because resolve_name falls through all the cases and reaches the Ok(None) at the end for what seems like all programs.

[mstange]

Oh, this new error only starts appearing if I add .with_functions(). With my original code (using the default options), mapping succeeds but locate returns Ok(None).

[fitzgen]

Seems like a compiler bug?

Care to file a bug with gcc?

We should still handle it by ignoring that subroutine, instead of raising an error.

👍

[philipc]

Care to file a bug with gcc?

I gave up on that, they don't make it easy to file bugs, and this one seems minor.