From @raydiak

22​:35​:18* raydiak | m​: multi sub cross () {}
22​:35​:19 +camelia | rakudo-moar 36c4c6​: OUTPUT«(signal SEGV)»

gdb backtrace at https://gist.github.com/flussence/fe3f1f829e3947b68d98 courtesy of fluessence++

http://irclog.perlgeek.de/perl6/2015-10-30#i_11459632 through 23​:15

From iteronvexor@gmail.com

This causes segmentation fault​:

perl6 -e "multi sub cross() { }"

This is Rakudo version 2016.03-106-gd847011 built on MoarVM version
2016.03-104-g10d3971
implementing Perl 6.c.

From @nwc10

On Thu, Apr 14, 2016 at 03​:22​:37PM -0700, Caligo Wall wrote​:

This causes segmentation fault​:

perl6 -e "multi sub cross() { }"

Thanks for the report.

It's an interesting failure - ASAN reports an out of bounds read​:

$ ./perl6-m -e "multi sub cross() { }"

==10839==ERROR​: AddressSanitizer​: heap-buffer-overflow on address 0x60300026c138 at pc 0x7f4e04aa7545 bp 0x7fffc486d790 sp 0x7fffc486d788
READ of size 8 at 0x60300026c138 thread T0
  #​0 0x7f4e04aa7544 in get_attribute src/6model/reprs/P6opaque.c​:227
  #​1 0x7f4e0495789f in MVM_interp_run src/core/interp.c​:1955
  #​2 0x7f4e04c33519 in MVM_vm_run_file src/moar.c​:303
  #​3 0x401a4f in main src/main.c​:191
  #​4 0x7f4e0417ed5c in __libc_start_main (/lib64/libc.so.6+0x1ed5c)
  #​5 0x401058 (/home/nicholas/Sandpit/moar-san/bin/moar+0x401058)

0x60300026c138 is located 8 bytes to the left of 24-byte region [0x60300026c140,0x60300026c158)
allocated by thread T0 here​:
  #​0 0x7f4e0555562f in __interceptor_malloc ../../.././libsanitizer/asan/asan_malloc_linux.cc​:72
  #​1 0x7f4e04b36799 in MVM_malloc src/core/alloc.h​:2
  #​2 0x7f4e04b4a09d in deserialize_stable src/6model/serialization.c​:2436
  #​3 0x7f4e04b4be9d in work_loop src/6model/serialization.c​:2597
  #​4 0x7f4e04b4c72f in MVM_serialization_demand_stable src/6model/serialization.c​:2667
  #​5 0x7f4e04b33be1 in MVM_sc_get_stable src/6model/sc.c​:244
  #​6 0x7f4e04b4815d in read_object_table_entry src/6model/serialization.c​:2145
  #​7 0x7f4e04b4da96 in repossess src/6model/serialization.c​:2828
  #​8 0x7f4e04b4ed51 in MVM_serialization_deserialize src/6model/serialization.c​:2986
  #​9 0x7f4e0496e8ea in MVM_interp_run src/core/interp.c​:3003
  #​10 0x7f4e04c33519 in MVM_vm_run_file src/moar.c​:303
  #​11 0x401a4f in main src/main.c​:191
  #​12 0x7f4e0417ed5c in __libc_start_main (/lib64/libc.so.6+0x1ed5c)

SUMMARY​: AddressSanitizer​: heap-buffer-overflow src/6model/reprs/P6opaque.c​:227 get_attribute
Shadow bytes around the buggy address​:
  0x0c06800457d0​: 00 fa fa fa 00 00 00 fa fa fa 00 00 00 00 fa fa
  0x0c06800457e0​: 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00 04 fa
  0x0c06800457f0​: fa fa 00 00 00 fa fa fa 00 00 00 00 fa fa 00 00
  0x0c0680045800​: 00 00 fa fa 00 00 00 00 fa fa 00 00 00 fa fa fa
  0x0c0680045810​: 00 00 00 00 fa fa 00 00 00 fa fa fa 00 00 00 fa
=>0x0c0680045820​: fa fa 00 00 00 fa fa[fa]00 00 00 fa fa fa 00 00
  0x0c0680045830​: 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa
  0x0c0680045840​: 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa
  0x0c0680045850​: fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00
  0x0c0680045860​: 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa
  0x0c0680045870​: 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes)​:
  Addressable​: 00
  Partially addressable​: 01 02 03 04 05 06 07
  Heap left redzone​: fa
  Heap right redzone​: fb
  Freed heap region​: fd
  Stack left redzone​: f1
  Stack mid redzone​: f2
  Stack right redzone​: f3
  Stack partial redzone​: f4
  Stack after return​: f5
  Stack use after scope​: f8
  Global redzone​: f9
  Global init order​: f6
  Poisoned by user​: f7
  Contiguous container OOB​:fc
  ASan internal​: fe
==10839==ABORTING

[hopefully with formatting fixed]

Nicholas Clark

The RT System itself - Status changed from 'new' to 'open'

From @timo

On 04/15/2016 09​:36 PM, Nicholas Clark wrote​:

multi sub cross() { }
Here's a gdb backtrace and a moarvm-level backtrace. Value looks a tiny
bit suspicious, though i don't know if there's actually anything wrong
with it.

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff78ef0d3 in get_attribute (tc=0x6037c0, st=0xe5a660,
root=0x7ffff6695bd8, data=0x7ffff6695bf0,
  class_handle=0xe5d1a8, name=pointer to '$!dispatchees', hint=5,
result_reg=0x70c648, kind=8)
  at src/6model/reprs/P6opaque.c​:242
242 MVMROOT(tc, value, {
(gdb) print value
$1 = (MVMObject *) 0x2104cc0
(gdb) print value[0]
$2 = {header = {sc_forward_u = {forwarder = 0x0, sc = {sc_idx = 0, idx =
0}, st = 0x0}, owner = 0, flags = 0,
  size = 0}, st = 0x0}
(gdb) print MVM_dump_backtrace(tc)
  at <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/BOOTSTRAP.moarvm​:)
from src/Perl6/World.nqp​:2222
(/home/timo/perl6/install/share/nqp/lib/Perl6/World.moarvm​:derive_dispatcher)
from gen/moar/m-Perl6-Actions.nqp​:3389
(/home/timo/perl6/install/share/nqp/lib/Perl6/Actions.moarvm​:routine_def)
from gen/moar/stage2/QRegex.nqp​:1342
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:!reduce)
from gen/moar/stage2/QRegex.nqp​:1303
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:!cursor_pass)
from src/Perl6/Grammar.nqp​:2581
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:routine_def)
from <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:routine_declarator​:sym<sub>)
from gen/moar/stage2/QRegex.nqp​:1379
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:!protoregex)
from <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:routine_declarator)
from src/Perl6/Grammar.nqp​:2360
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:declarator)
from src/Perl6/Grammar.nqp​:2374
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:multi_declarator​:sym<multi>)
from gen/moar/stage2/QRegex.nqp​:1379
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:!protoregex)
from <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:multi_declarator)
from <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:term​:sym<multi_declarator>)
from gen/moar/stage2/QRegex.nqp​:1379
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:!protoregex)
from <unknown>​:1
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:term)
from src/Perl6/Grammar.nqp​:3740
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:termish)
from gen/moar/stage2/NQPHLL.nqp​:860
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:EXPR)
from src/Perl6/Grammar.nqp​:3775
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:EXPR)
from src/Perl6/Grammar.nqp​:1232
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:statement)
from src/Perl6/Grammar.nqp​:1161
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:statementlist)
from gen/moar/stage2/NQPHLL.nqp​:1084
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:LANG)
from src/Perl6/Grammar.nqp​:1551
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:FOREIGN_LANG)
from src/Perl6/Grammar.nqp​:1145
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:comp_unit)
from src/Perl6/Grammar.nqp​:448
(/home/timo/perl6/install/share/nqp/lib/Perl6/Grammar.moarvm​:TOP)
from gen/moar/stage2/QRegex.nqp​:2093
(/home/timo/perl6/install/share/nqp/lib/QRegex.moarvm​:parse)
from gen/moar/stage2/NQPHLL.nqp​:1787
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:parse)
from gen/moar/stage2/NQPHLL.nqp​:1743
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:compile)
from gen/moar/stage2/NQPHLL.nqp​:1479
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:eval)
from src/Perl6/Compiler.nqp​:161
(/home/timo/perl6/install/share/nqp/lib/Perl6/Compiler.moarvm​:eval)
from gen/moar/stage2/NQPHLL.nqp​:1587
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:)
from gen/moar/stage2/NQPHLL.nqp​:1584
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:command_eval)
from src/Perl6/Compiler.nqp​:29
(/home/timo/perl6/install/share/nqp/lib/Perl6/Compiler.moarvm​:command_eval)
from gen/moar/stage2/NQPHLL.nqp​:1568
(/home/timo/perl6/install/share/nqp/lib/NQPHLL.moarvm​:command_line)
from gen/moar/m-main.nqp​:37
(/home/timo/perl6/install/share/perl6/runtime/perl6.moarvm​:MAIN)
from gen/moar/m-main.nqp​:33
(/home/timo/perl6/install/share/perl6/runtime/perl6.moarvm​:<mainline>)
from <unknown>​:1
(/home/timo/perl6/install/share/perl6/runtime/perl6.moarvm​:<main>)
from <unknown>​:1
(/home/timo/perl6/install/share/perl6/runtime/perl6.moarvm​:<entry>)
$3 = void
(gdb) bt full
#​0 0x00007ffff78ef0d3 in get_attribute (tc=0x6037c0, st=0xe5a660,
root=0x7ffff6695bd8, data=0x7ffff6695bf0,
  class_handle=0xe5d1a8, name=pointer to '$!dispatchees', hint=5,
result_reg=0x70c648, kind=8)
  at src/6model/reprs/P6opaque.c​:242
  cloned = 0x3cf
  value = 0x2104cc0
  result = 0x0
  attr_st = 0x0
  repr_data = 0x2104b80
  slot = 5

From @zoffixznet

On Fri, 30 Oct 2015 20​:29​:37 -0700, raydiak@​cyberuniverses.com wrote​:

22​:35​:18* raydiak | m​: multi sub cross () {}
22​:35​:19 +camelia | rakudo-moar 36c4c6​: OUTPUT«(signal SEGV)»

gdb backtrace at
https://gist.github.com/flussence/fe3f1f829e3947b68d98 courtesy of
fluessence++

http://irclog.perlgeek.de/perl6/2015-10-30#i_11459632 through 23​:15

Thank you for the report. This is now fixed.

Fix​: rakudo/rakudo@998a1ef1
Test​: Raku/roast@7cc4622b62

@zoffixznet - Status changed from 'open' to 'resolved'