[srslte-users] seg fault when running pdsch_enodeb with -p > 15 (X300 box)

Jasuja, Ishwar Ishwar.Jasuja at spirent.com
Wed Jun 22 00:51:25 UTC 2016


Hi,

I found psss_ursp test app in the srsLTE code and decided to try that (instead of pdsch_ue)  to simplify things.

What I noticed is that "Pos" field value does not stay constant when eNodeB is running with channel bandwidths >= 5 Mhz.
For lower two values of bandwidths (no_prb=6 & 15), it is fairly constant (decrements only by one every 1000 iterations or so).

So looks like the correlation peak value (in srslte_pss_synch_find_pss()) is all over the place for higher bandwidth values.
I tried disabling freq. domain convolution (undefined CONVOLUTION_FFT in pss.h) but that did not make any diff.

Any help will be greatly appreciated!!

Thanks,
Ishwar

From: Jasuja, Ishwar
Sent: Tuesday, June 21, 2016 10:58 AM
To: 'Ismael Gomez'; srslte-users at lists.softwareradiosystems.com
Subject: seg fault when running pdsch_enodeb with -p > 15 (X300 box)

Hi,

I am getting segmentation fault when I try to run at channel bandwidth >= 5MHz. Stack trace show below.

I increased the size for following allocation and segmentation fault stopped occurring  but pdsch_ue fails to find pss.
Things seem to work fine for nof_prb = 6 & 15.


  output_buffer = srslte_vec_malloc(4 * sizeof(cf_t) * sf_n_samples);
  if (!output_buffer) {
    perror("malloc");
    exit(-1);
  }


Let me know if you need me to provide any more information.

Can you point me to an area of code where I can dig in and put more debug messages to figure out what is going on?

Thanks,
Ishwar

Note: I am using two X300 Ettus boxes connected b2b with SMA cable (20db attenuator)

./pdsch_enodeb -a "type=x300,master_clock_rate=184.32e6" -f 2000000000 -p 25  (one of the debug message: Setting sampling rate 5.76 MHz)

./pdsch_ue -f 2000000000 -g 30 -a "type=x300,master_clock_rate=184.32e6" -p 25 ([INFO]:  Setting sampling frequency 1.92 MHz for PSS search)


Program received signal SIGSEGV, Segmentation fault.
0x00007f8aca2c2e43 in uhd_tx_streamer_send () from /usr/local/lib/libuhd.so.003
(gdb) bt
#0  0x00007f8aca2c2e43 in uhd_tx_streamer_send () from /usr/local/lib/libuhd.so.003
#1  0x00007f8acb783959 in rf_uhd_send_timed (h=0x233aa90, data=0x234b540, nsamples=11520, secs=<optimized out>, frac_secs=<optimized out>, has_time_spec=<optimized out>,
    blocking=<optimized out>, is_start_of_burst=true, is_end_of_burst=false) at /home2/ijasuja/srsLTE/srslte/lib/rf/rf_uhd_imp.c:525
#2  0x00007f8acb7821df in srslte_rf_send_timed3 (is_end_of_burst=is_end_of_burst at entry=false, is_start_of_burst=is_start_of_burst at entry=false, blocking=blocking at entry=true,
    has_time_spec=false, frac_secs=0, secs=0, nsamples=<optimized out>, data=<optimized out>, rf=rf at entry=0x631e00 <rf>) at /home2/ijasuja/srsLTE/srslte/lib/rf/rf_imp.c:276
#3  srslte_rf_send2 (rf=rf at entry=0x631e00 <rf>, data=<optimized out>, nsamples=<optimized out>, blocking=blocking at entry=true, start_of_burst=start_of_burst at entry=true,
    end_of_burst=end_of_burst at entry=false) at /home2/ijasuja/srsLTE/srslte/lib/rf/rf_imp.c:287
#4  0x0000000000402c0c in main (argc=<optimized out>, argv=<optimized out>) at /home2/ijasuja/srsLTE/srslte/examples/pdsch_enodeb.c:713
(gdb)





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