'Attempt to substract with overflow' in linux/symbolication

[aldanor]

Tried running crate tests on CentOS 7, with libunwind built manually (due to issues linking to the system-wide one, described in another issue), both vs the system Python and with Python 3.6 from conda installation.

All unit tests pass, but all integration tests fail with a weird overflow error:

'test_busy_loop' panicked at 'attempt to subtract with overflow', 
remoteprocess/src/linux/symbolication.rs:90:40

Looks like this subtraction is failing:

py-spy/remoteprocess/src/linux/symbolication.rs

Lines 89 to 90 in d167236

	let obj_base = match program_header {
	Some(hdr) => { m.start() as u64 - hdr.p_vaddr },

Full backtrace

---- test_busy_loop stdout ----
thread 'test_busy_loop' panicked at 'attempt to subtract with overflow', remoteprocess/src/linux/symbolication.rs:90:40
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:47
   3: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:36
   4: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:200
   5: std::panicking::default_hook
             at src/libstd/panicking.rs:211
   6: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:477
   7: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:384
   8: rust_begin_unwind
             at src/libstd/panicking.rs:311
   9: core::panicking::panic_fmt
             at src/libcore/panicking.rs:85
  10: core::panicking::panic
             at src/libcore/panicking.rs:49
  11: remoteprocess::linux::symbolication::Symbolicator::reload
             at remoteprocess/src/linux/symbolication.rs:90
  12: remoteprocess::linux::symbolication::Symbolicator::new
             at remoteprocess/src/linux/symbolication.rs:28
  13: remoteprocess::linux::Process::symbolicator
             at remoteprocess/src/linux/mod.rs:113
  14: py_spy::native_stack_trace::NativeStack::new
             at src/native_stack_trace.rs:32
  15: py_spy::python_spy::PythonSpy::new
             at src/python_spy.rs:111
  16: py_spy::python_spy::PythonSpy::retry_new
             at src/python_spy.rs:131
  17: integration_test::TestRunner::new
             at tests/integration_test.rs:14
  18: integration_test::test_busy_loop
             at tests/integration_test.rs:37
  19: integration_test::test_busy_loop::{{closure}}
             at tests/integration_test.rs:29
  20: core::ops::function::FnOnce::call_once
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libcore/ops/function.rs:231
  21: <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/liballoc/boxed.rs:746
  22: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:82
  23: std::panicking::try
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/panicking.rs:275
  24: std::panic::catch_unwind
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/panic.rs:394
  25: test::run_test::run_test_inner::{{closure}}
             at src/libtest/lib.rs:1466

[benfred]

I just tried this with Centos7 (using the py-spy v0.2.2 installed via pip) and it worked fine for me - with both the v2.7.5 and v3.6.8 versions installed through yum =(.

Does this just happen in the integration tests?

[benfred]

Still haven't managed to reproduce - but #187 there should fix the problem hopefully

[benfred]

Fix is in v0.3.0 - let me know if this doesn't work out for you