Re: [Discuss-gnuradio] usrp_spectrum_sense.py segmentation fault problem

[Sebastian Döring]

On Tue, 20 Dec 2011 20:24:28 -0500
 Tom Rondeau <address@hidden> wrote:
> On Tue, Dec 20, 2011 at 11:02 AM, Thomas Tsou 
> <address@hidden> wrote:
>
> > On Tue, Dec 20, 2011 at 5:11 AM, Sebastian Döring
> > <address@hidden> wrote:
> > >>
> > ------------------------------------------------------------------------------------------------------
> > >> #0  0x0013a455 in sem_post@@GLIBC_2.1 () from
> > >> /lib/tls/i686/cmov/libpthread.so.0
> > >> #1  0x0810ab61 in PyThread_release_lock (lock=0x0) at
> > >> ../Python/thread_pthread.h:374
> > >> #2  0x080dbad3 in PyEval_ReleaseLock () at 
> > ../Python/ceval.c:262
> > >> #3  0x00fa6073 in gr_py_feval_dd::calleval(double) ()
> >
> > This is likely a similar issue with the Python GIL 
> > (global interpreter
> > lock) that occurred previously on the E100. In that case 
> > the final
> > cause was a missing ctypes library.
> >
> >
> > http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2011-June/001479.html
> >
> > To find out, try this thread hack. The patch is old, so 
> > you will
> > probably need to apply manually against the current 
> > master.
> >
> > diff --git a/uhd_spectrum_sense_sum.py 
> > b/uhd_spectrum_sense_sum.py
> > index 70f530f..31bf458 100644
> > --- a/uhd_spectrum_sense_sum.py
> > +++ b/uhd_spectrum_sense_sum.py
> > @@ -32,7 +32,11 @@ import sys
> >  import math
> >  import struct
> >  import time
> > +import threading
> >
> > +class ThreadClass(threading.Thread):
> > +    def run(self):
> > +        return
> >
> >  class tune(gr.feval_dd):
> >    """
> > @@ -306,6 +310,9 @@ def main_loop(tb):
> >
> >
> >  if __name__ == '__main__':
> > +    t = ThreadClass()
> > +    t.start()
> > +
> >    tb = my_top_block()
> >    try:
> >        tb.start()              # start executing flow 
> > graph in
> > another thread...
> >
> >  Thomas
>
>
>
> Please let us know if this patch works. I think this has 
> been an
> outstanding issue in GNU Radio for a while. It'd be good 
> to get a fix for
> it in.
>
> Thanks,
> Tom

Thank you guys - it worked!
The line positions have a changed a bit and so I simply 
attached the new code (gnuradio build 20.12.2011).

--- a/usrp_spectrum_sense.py	2011-12-20 12:44:55.000000000 
+0100
+++ b/usrp_spectrum_sense.py	2011-12-21 14:26:19.252873684 
+0100
@@ -28,9 +28,14 @@
 import sys
 import math
 import struct
+import threading
 
 sys.stderr.write("Warning: this is known to have issues 
on some machines+Python version combinations to seg fault 
due to the callback in bin_statitics. If you figure out 
why, we'd love to hear about it!\n")
 
+class ThreadClass(threading.Thread):
+    def run(self):
+        return
+
 class tune(gr.feval_dd):
     """
     This class allows C++ code to callback into python.
@@ -240,6 +245,9 @@
 

 if __name__ == '__main__':
+    t = ThreadClass()
+    t.start()
+
     tb = my_top_block()
     try:
         tb.start()

Regards
Sebastian