[erlang-questions] Segfault in NIF call

Fredrik Linder <>
Mon Apr 29 20:57:14 CEST 2013


Found one error (yay!) -- enif_open_resource_type should have NULL as the
module argument (missed this one in the docs)

Running with cerl does not generate a segfault, nor any (extra) printouts
Running with erl still generate segfault

Now I get either of the following (using erl), does it reveal what my error
is?

> USE_GDB=1 rebar eunit
[cut]
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x2aaaad6c0700 (LWP 6384)]
0x000000000052b28a in process_main () at
x86_64-unknown-linux-gnu/opt/smp/beam_hot.h:979
979    MoveDeallocateReturn(xb(tmp_packed1&BEAM_LOOSE_MASK), r(0),
Qb((tmp_packed1>>BEAM_LOOSE_SHIFT)));
(gdb) backtrace
#0  0x000000000052b28a in process_main () at
x86_64-unknown-linux-gnu/opt/smp/beam_hot.h:979
#1  0x0000000000491463 in sched_thread_func (vesdp=0x2aaaac343ac0) at
beam/erl_process.c:5632
#2  0x0000000000590440 in thr_wrapper (vtwd=0x7fffffffd850) at
pthread/ethread.c:106
#3  0x00002aaaab3ffe9a in start_thread (arg=0x2aaaad6c0700) at
pthread_create.c:308
#4  0x00002aaaab911cbd in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

or

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x2aaaad6c0700 (LWP 6914)]
unlink_free_block (allctr=0x85e5c0, block=0x0, flags=0) at
beam/erl_goodfit_alloc.c:458
458    Uint sz = MBC_FBLK_SZ(&blk->block_head);
(gdb) backtrace
#0  unlink_free_block (allctr=0x85e5c0, block=0x0, flags=0) at
beam/erl_goodfit_alloc.c:458
#1  0x0000000000444ee1 in get_free_block (allctr=0x85e5c0, size=<optimized
out>, cand_blk=0x0, cand_size=0, flags=0) at beam/erl_goodfit_alloc.c:426
#2  0x000000000043b6da in mbc_alloc_block (alcu_flgsp=<synthetic pointer>,
blk_szp=<synthetic pointer>, size=<optimized out>, allctr=0x85e5c0) at
beam/erl_alloc_util.c:1309
#3  mbc_alloc (allctr=0x85e5c0, size=<optimized out>) at
beam/erl_alloc_util.c:1451
#4  0x0000000000440d7b in do_erts_alcu_alloc (size=32, extra=0x85e5c0,
type=148) at beam/erl_alloc_util.c:3530
#5  erts_alcu_alloc_thr_pref (type=148, extra=<optimized out>,
size=<optimized out>) at beam/erl_alloc_util.c:3607
#6  0x0000000000490595 in erts_alloc (size=32, type=18967) at
beam/erl_alloc.h:208
#7  new_message_buffer (size=0) at beam/erl_message.c:72
#8  erts_alloc_message_heap_state (statep=0x2aaaad6bfc4c,
receiver_locks=0x2aaaad6bfcb0, receiver=0x2aaaac9c1db8, ohpp=<synthetic
pointer>, bpp=<synthetic pointer>, size=0) at beam/global.h:1017
#9  erts_send_message (sender=0x2aaaac9c2470, receiver=0x2aaaac9c1db8,
receiver_locks=0x2aaaad6bfcb0, message=564171, flags=<optimized out>) at
beam/erl_message.c:1039
#10 0x0000000000476350 in do_send (p=0x2aaaac9c2470, to=793099, msg=564171,
suspend=1, refp=<optimized out>) at beam/bif.c:2025
#11 0x0000000000476bf0 in erl_send (p=0x2aaaac9c2470, to=793099,
msg=564171) at beam/bif.c:2138
#12 0x000000000052d1d8 in process_main () at beam/beam_emu.c:2558
#13 0x0000000000491463 in sched_thread_func (vesdp=0x2aaaac343ac0) at
beam/erl_process.c:5632
#14 0x0000000000590440 in thr_wrapper (vtwd=0x7fffffffd850) at
pthread/ethread.c:106
#15 0x00002aaaab3ffe9a in start_thread (arg=0x2aaaad6c0700) at
pthread_create.c:308
#16 0x00002aaaab911cbd in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#17 0x0000000000000000 in ?? ()


/Fredrik






On Mon, Apr 29, 2013 at 2:58 AM, Sverker Eriksson <
> wrote:

> Looks like some sort of memory corruption.
>
> Run on debug emulator and hope for a better (earlier) crash.
>
> # cd $ERL_TOP/erts/emulator
> # make TYPE=debug smp plain
> # $ERL_TOP/bin/cerl -debug
>
> /Sverker, Erlang/OTP Ericsson
>
>  wrote:
>
>> Hello folks,
>>
>> I'm having difficulties locating the cause of a segfault I'm getting when
>> running tests with a NIF implementation I have.
>>
>> Anything that would shed light on what's wrong is appreciated.
>>
>> The backtrace does not seem to have anything to do with my NIF. The
>> NIF:ed function is called from a few different processes, and it forwards
>> the call to a worker thread which sends a message back to the caller
>> process.
>>
>>
>>
>>> strings -a
>>>
>> ../../otp/R16B/pre-5.10.1-mz-**0.2/lib/erlang/erts-5.10.1/**bin/beam.smp|fgrep
>> GCC|sort -u
>> GCC: (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
>>
>>
>>
>>> USE_GDB=1 rebar eunit
>>>
>>>
>> [cut]
>> Program received signal SIGSEGV, Segmentation fault.
>> [Switching to Thread 0x2aaaef381700 (LWP 19162)]
>> unlink_free_block (allctr=0x85f240, block=0x0, flags=0) at
>> beam/erl_goodfit_alloc.c:458
>> 458    Uint sz = MBC_FBLK_SZ(&blk->block_head);
>> (gdb) backtrace
>> #0  unlink_free_block (allctr=0x85f240, block=0x0, flags=0) at
>> beam/erl_goodfit_alloc.c:458
>> #1  0x0000000000444ee1 in get_free_block (allctr=0x85f240,
>> size=<optimized out>, cand_blk=0x0, cand_size=0, flags=0) at
>> beam/erl_goodfit_alloc.c:426
>> #2  0x000000000043b6da in mbc_alloc_block (alcu_flgsp=<synthetic
>> pointer>, blk_szp=<synthetic pointer>, size=<optimized out>,
>> allctr=0x85f240) at beam/erl_alloc_util.c:1309
>> #3  mbc_alloc (allctr=0x85f240, size=<optimized out>) at
>> beam/erl_alloc_util.c:1451
>> #4  0x0000000000440d7b in do_erts_alcu_alloc (size=32, extra=0x85f240,
>> type=148) at beam/erl_alloc_util.c:3530
>> #5  erts_alcu_alloc_thr_pref (type=148, extra=<optimized out>,
>> size=<optimized out>) at beam/erl_alloc_util.c:3607
>> #6  0x0000000000490595 in erts_alloc (size=32, type=18967) at
>> beam/erl_alloc.h:208
>> #7  new_message_buffer (size=0) at beam/erl_message.c:72
>> #8  erts_alloc_message_heap_state (statep=0x2aaaef380c4c,
>> receiver_locks=0x2aaaef380cb0, receiver=0x2aaaac9ccac8, ohpp=<synthetic
>> pointer>, bpp=<synthetic pointer>, size=0) at beam/global.h:1017
>> #9  erts_send_message (sender=0x2aaaac9cd118, receiver=0x2aaaac9ccac8,
>> receiver_locks=0x2aaaef380cb0, message=513931, flags=<optimized out>) at
>> beam/erl_message.c:1039
>> #10 0x0000000000476350 in do_send (p=0x2aaaac9cd118, to=550027,
>> msg=513931, suspend=1, refp=<optimized out>) at beam/bif.c:2025
>> #11 0x0000000000476bf0 in erl_send (p=0x2aaaac9cd118, to=550027,
>> msg=513931) at beam/bif.c:2138
>> #12 0x000000000052d1d8 in process_main () at beam/beam_emu.c:2558
>> #13 0x0000000000491463 in sched_thread_func (vesdp=0x2aaaac34de40) at
>> beam/erl_process.c:5632
>> #14 0x0000000000590440 in thr_wrapper (vtwd=0x7fffffffd7e0) at
>> pthread/ethread.c:106
>> #15 0x00002aaaab3ffe9a in start_thread (arg=0x2aaaef381700) at
>> pthread_create.c:308
>> #16 0x00002aaaab911cbd in clone () at ../sysdeps/unix/sysv/linux/**
>> x86_64/clone.S:112
>> #17 0x0000000000000000 in ?? ()
>> (gdb)
>>
>>   ------------------------------**------------------------------**
>> ------------
>>
>> ______________________________**_________________
>> erlang-questions mailing list
>> 
>> http://erlang.org/mailman/**listinfo/erlang-questions<http://erlang.org/mailman/listinfo/erlang-questions>
>>
>>
>
>
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