Possibly JIT related

gistfile1.txt

dogbert@dogbert-VirtualBox ~/repos/rakudo $ ./perl6-gdb-m t/spec/S03-operators/set_multiply.t
================================================================================================
This is Rakudo Perl 6 running in the GNU debugger, which often allows the user to generate useful back-
traces to debug or report issues in Rakudo, the MoarVM backend or the currently running code.

This Rakudo version is 2018.09.437.g.31.b.19.d.0 built on MoarVM version 2018.09.128.g.95.d.2279,
running on linuxmint (18.3.Sylvia) / linux (4.10.0.38.generic)

Type `bt full` to generate a backtrace if applicable, type `q` to quit or `help` for help.
------------------------------------------------------------------------------------------------
Reading symbols from /home/dogbert/repos/rakudo/install/bin/moar...done.
Starting program: /home/dogbert/repos/rakudo/install/bin/moar --execname=./perl6-gdb-m --libpath=. --libpath=blib --libpath=/home/dogbert/repos/rakudo/install/share/nqp/lib --libpath=/home/dogbert/repos/rakudo/install/share/nqp/lib --libpath=/home/dogbert/repos/rakudo/install/share/nqp/lib /home/dogbert/repos/rakudo/perl6.moarvm --nqp-lib=blib t/spec/S03-operators/set_multiply.t
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff6608700 (LWP 23939)]
1..586
ok 1 - does (.)() return bag()
ok 2 - Sequence of empty Set is the empty Bag
    1..2
    ok 1 - code dies
    ok 2 - right exception type (X::Cannot::Lazy)
...
ok 498 - [⊍] a	True
# b	True
# c	True Mix(c, d, e) b	True
# c	True
# d	True

Thread 1 "moar" hit Breakpoint 1, MVM_panic (exitCode=1, messageFormat=0x7ffff76f9398 "Collectable %p in fromspace accessed") at src/core/exceptions.c:821
821	MVM_NO_RETURN void MVM_panic(MVMint32 exitCode, const char *messageFormat, ...) {
(gdb) bt
#0  MVM_panic (exitCode=1, messageFormat=0x7ffff76f9398 "Collectable %p in fromspace accessed") at src/core/exceptions.c:821
#1  0x00007ffff7588025 in push (tc=0x604a50, st=0x665270, root=0x7bb290, data=0x7bb2a8, value=..., kind=8) at src/6model/reprs/VMArray.c:480
#2  0x00007ffff757f0d6 in MVM_repr_push_o (tc=0x604a50, obj=0x7bb290, pushee=0x6110c0) at src/6model/reprconv.c:379
#3  0x00007ffff762890b in evaluate_guards (tc=0x604a50, gs=0x4e7c5f8, callsite=0x7ffff7cad320 <inv_arg_callsite>, guard_offset=0x7fffffffc21e) at src/spesh/plugin.c:91
#4  0x00007ffff7628a27 in resolve_using_guards (tc=0x604a50, cur_position=128, callsite=0x7ffff7cad320 <inv_arg_callsite>, guard_offset=0x7fffffffc21e, sf=0x11c2a60) at src/spesh/plugin.c:119
#5  0x00007ffff762a448 in MVM_spesh_plugin_resolve_jit (tc=0x604a50, name=0x1816940, result=0x50617c0, position=128, sf=0x11c2a60, callsite=0x7ffff7cad320 <inv_arg_callsite>) at src/spesh/plugin.c:455
#6  0x00007fffeff18270 in ?? ()
#7  0x0000000000000008 in ?? ()
#8  0x0000000004d7dd00 in ?? ()
#9  0x00007fffffffc290 in ?? ()
#10 0x00007ffff753d666 in MVM_fixed_size_free (tc=0x7ffff7593f6a <bind_attribute>, al=0x7fffffffc380, bytes=140737343209322, to_free=0x17dea80) at src/core/fixedsizealloc.c:299
#11 0x00007ffff76afca4 in MVM_jit_code_enter (tc=0x604a50, code=0x7ffff0c44b00, cu=0x698360) at src/jit/interface.c:24
#12 0x00007ffff7510b3e in MVM_interp_run (tc=0x604a50, initial_invoke=0x7ffff768dfe3 <toplevel_initial_invoke>, invoke_data=0x6a7b28) at src/core/interp.c:5977
#13 0x00007ffff768e148 in MVM_vm_run_file (instance=0x604010, filename=0x7fffffffe269 "/home/dogbert/repos/rakudo/perl6.moarvm") at src/moar.c:440
#14 0x00000000004016e7 in main (argc=10, argv=0x7fffffffddc8) at src/main.c:301
(gdb) info threads
  Id   Target Id         Frame 
* 1    Thread 0x7ffff7fdb700 (LWP 23954) "moar" MVM_panic (exitCode=1, messageFormat=0x7ffff76f9398 "Collectable %p in fromspace accessed") at src/core/exceptions.c:821
  2    Thread 0x7ffff6608700 (LWP 23955) "moar" pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
(gdb)