Re: [Discuss-gnuradio] constellation soft decoder

[Miklos Maroti]

Hi Marcus,

I do not think it is a compiler bug, but something uninitialized.
Constellation_qpsk and constellation_calcdist does not crash (I did
not verify if they work). However, if I generate the LUT for
constellation_qpsk, then it crashes.

# uname -a
Linux maroti-t410 3.11.0-14-generic #21-Ubuntu SMP Tue Nov 12 17:04:55
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

# gcc --version
gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1

Using latest master branch of gnuradio, hash 117058bac41c91, both
CMAKE_BUILD_TYPE=Debug and Release produces the same behavior

# gdb `which python` core
Reading symbols from /usr/bin/python2.7...(no debugging symbols found)...done.

warning: core file may not match specified executable file.
[New LWP 2249]
[New LWP 2251]
[New LWP 2240]
[New LWP 2248]
[New LWP 2247]
[New LWP 2239]
[New LWP 2250]

warning: Can't read pathname for load map: Input/output error.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `python ./constellation_simulation.py'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f98dbbe01a7 in gr::digital::constellation::calc_soft_dec (
    this=0x48321c0, sample=..., npwr=<optimized out>)
    at /home/mmaroti/workspace/gnuradio/gr-digital/lib/constellation.cc:286
286        for(int j = 0; j < k; j++) {

i stack
#0  0x00007f98dbbe01a7 in gr::digital::constellation::calc_soft_dec (
    this=0x48321c0, sample=..., npwr=<optimized out>)
    at /home/mmaroti/workspace/gnuradio/gr-digital/lib/constellation.cc:286
#1  0x00007f98dbbe0f7e in gr::digital::constellation::soft_decision_maker (
    this=0x48321c0, sample=...)
    at /home/mmaroti/workspace/gnuradio/gr-digital/lib/constellation.cc:355
#2  0x00007f98dbbe94dc in
gr::digital::constellation_soft_decoder_cf_impl::work (this=0x4fb11a0,
noutput_items=8190, input_items=..., output_items=...)
    at 
/home/mmaroti/workspace/gnuradio/gr-digital/lib/constellation_soft_decoder_cf_impl.cc:68
#3  0x00007f98e1c5dd38 in gr::sync_interpolator::general_work (
    this=0x4fb11c0, noutput_items=<optimized out>, ninput_items=...,
    input_items=..., output_items=...)
    at 
/home/mmaroti/workspace/gnuradio/gnuradio-runtime/lib/sync_interpolator.cc:67

You should be able to reproduce the problem quite easily, but if
needed I can provided a test program.

Best,
Miklos

On Mon, Dec 16, 2013 at 7:59 AM, Marcus Müller <address@hidden> wrote:
> Could you post the whole backtrace (as a github gist, pastebin etc)?
> That would be very helpful, along with information such as:
> Compiler (Gcc (version), VC++, clang ...), Platform (Linux, win, mac,...),
> architecture (x86(64), ARMv9, IBM S7390,...) and GNU Radio source version.
>
> Thanks and happy hacking,
> Marcus
>
> On 12/16/2013 01:05 AM, Miklos Maroti wrote:
>>
>> Hi Guys,
>>
>> Constellation soft decoder crashes for constellation_bpsk() and
>> constellation_8psk(). I could not find the cause of this problem, the
>> back trace on my machine points to
>>
>> gnuradio/gr-digital/lib/constellation.cc:286
>>       for(int j = 0; j < k; j++) {
>>
>> which does not make any sense. Any idea what could go wrong?
>>
>> Miklos
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
>
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