Hi Daniel,
Thanks for the message. The scenario you talk about only happens if GC
is a shared library, right?

I've rebuilt GC disabling shared libs, and ECL doing static linking to GC.
And I still get very similar segfaults:

;;; ECL C Backtrace
;;;    0 ecl_internal_error (0x87d79b375)
;;;    1 init_unixint (0x87d7c17e0)
;;;    2 init_unixint (0x87d7c1582)
;;;    3 pthread_sigmask (0x80103779d)
;;;    4 pthread_getspecific (0x801036d6f)
;;;    5 unknown (0x7ffffffff193)
;;;    6 GC_push_current_stack (0x87d7ef7c3)
;;;    7 GC_with_callee_saves_pushed (0x87d7f7360)
;;;    8 GC_push_roots (0x87d7ef9c2)
;;;    9 GC_mark_some (0x87d7ec97c)
;;;   10 GC_stopped_mark (0x87d7e6b7a)
;;;   11 GC_try_to_collect_inner (0x87d7e6a75)
;;;   12 GC_init (0x87d7f08ea)
;;;   13 init_alloc (0x87d7d5669)
;;;   14 cl_boot (0x87d69f66b)
...

And a very similar picture on the develop branch of ECL - although
I had to change our code, as  in particular
ECL_OPT_TRAP_SIGCHLD is gone...

So, what can it be? Some signals issue?

Thanks,
Dima

On Fri, Sep 1, 2017 at 7:38 AM, Daniel Kochmański <daniel@turtleware.eu> wrote:
 Hey Dima,

 this looks like the issue with having GC initialized before ECL kicks in.
 See https://gitlab.com/embeddable-common-lisp/ecl/issues/371 for a
 discussion about this problem. Basically some other component already called
 GC_init and ECL calls it once more. It's arguably not a bug.

 Best regards,

 Daniel

 On 31.08.2017 15:29, Dima Pasechnik wrote:

 Dear all,

 I'm struggling to understand strange segfaults coming from
 ECL(+Maxima) on FreeBSD embedded into Python; they typically look as
 follows:

 Got signal before environment was installed on our thread
    [2: No such file or directory]

 ;;; ECL C Backtrace
 ;;;    0 ecl_internal_error (0x87d790765)
 ;;;    1 init_unixint (0x87d7b6bd0)
 ;;;    2 init_unixint (0x87d7b6972)
 ;;;    3 pthread_sigmask (0x80103779d)
 ;;;    4 pthread_getspecific (0x801036d6f)
 ;;;    5 unknown (0x7ffffffff193)
 ;;;    6 GC_push_all_stacks (0x87db1ea2c)
 ;;;    7 GC_mark_some (0x87db12eec)
 ;;;    8 GC_stopped_mark (0x87db09baa)
 ;;;    9 GC_try_to_collect_inner (0x87db09a75)
 ;;;   10 GC_init (0x87db16f4f)
 ;;;   11 init_alloc (0x87d7caa59)
 ;;;   12 cl_boot (0x87d694a5b)
 ;;;   13 initecl (0x87d218340)
 ;;;   14 initecl (0x87d20a43f)
 ;;;   15 initecl (0x87d207e28)
 ;;;   16 _PyImport_LoadDynamicModule (0x800b3ed1c)
 ;;;   17 PyImport_AppendInittab (0x800b3d71f)
 ;;;   18 PyImport_AppendInittab (0x800b3d1a8)
 ;;;   19 PyImport_ImportModuleLevel (0x800b3c2ce)
 ;;;   20 _PyBuiltin_Init (0x800b162d7)
 ;;;   21 PyObject_Call (0x800a7d3e3)
 ;;;   22 PyEval_EvalFrameEx (0x800b2121c)
 ;;;   23 PyEval_EvalCodeEx (0x800b1b5d4)
 ;;;   24 PyEval_EvalCode (0x800b1ad96)
 ;;;   25 PyImport_ExecCodeModuleEx (0x800b3ad11)
 ;;;   26 PyImport_AppendInittab (0x800b3ddb8)
 ;;;   27 PyImport_AppendInittab (0x800b3d71f)
 ;;;   28 PyImport_AppendInittab (0x800b3d1a8)
 ;;;   29 PyImport_ImportModuleLevel (0x800b3c2ce)
 ;;;   30 _PyBuiltin_Init (0x800b162d7)
 ;;;   31 PyEval_EvalFrameEx (0x800b22dd1)
 Segmentation fault (core dumped)

 It looks as if ECL (version 16.1.2) is being called before an
 initialisation is complete, but it it possible to say more without a
 debugger?

 More details: is is on FreeBSD 11.0, clang 3.8.0, GC version 7.6.0
 with libatomic_ops version 7.4.6.
 And only reproducible on FreeBSD.

 ECL is built with --disable-threads; GC is built with or without
 threads---result is still the same.
 (so it's unclear to me where pthread_* calls in the trace
 come from).

 Thanks,
 Dima

 PS. the segfault is at the bottom of
 https://trac.sagemath.org/ticket/22679#comment:87