Trouble with latest GIT of Gnu Radio

Environment: 3 different computers, all running F12 with all latest
updates
Both USRP2 and USRP1

Latest GIT

A segfault is provoked in gr_sync_decimator.cc:64 when you have an
FFT filter, and change its size
at runtime.

Doesn’t matter which circbuf factory I’m using, or which of my 3 systems
(two are x86_64 and one is x86).

Doesn’t matter whether the FFT filter is “big” or little. Increasing
one from 2 taps to 128 taps was enough
to cause a segmentation fault.

Doesn’t seem to matter whether you’re increasing the size, or decreasing
it.


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

On Sat, Jul 3, 2010 at 8:17 PM, Marcus D. Leech [email protected]
wrote:

(two are x86_64 and one is x86).
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

Marcus,

I can’t seem to replicate this problem on my Ubuntu 10.04 64-bit
machine.

I created a signal, fft filter (ccc), and a file sink with a
threshold, connected them, and ran the flow graph. To run it, I used
this, where mytb is the top_block class.

def main():
taps0 = gr.firdes.low_pass_2(1, 1, 0.1, 0.1, 60)
taps1 = gr.firdes.low_pass_2(1, 1, 0.01, 0.01, 60)

print "Setting start taps (ntaps = %d)" % (len(taps0))
tb = mytb(taps0)
tb.start()

time.sleep(0.5)

print "Setting new taps (ntaps = %d)" % (len(taps1))
tb.fftfilt.set_taps(taps1)

time.sleep(0.5)

tb.stop()
tb.wait()

The initial taps have length 27 and the new taps (taps1) have length
273. I also tried it with both complex in/out/taps and float
in/out/taps.

Is there something else that I’m missing?

Tom

On 07/05/2010 12:03 PM, Tom R. wrote:


I created a signal, fft filter (ccc), and a file sink with a

The initial taps have length 27 and the new taps (taps1) have length
273. I also tried it with both complex in/out/taps and float
in/out/taps.

Is there something else that I’m missing?

Tom

Well, on my 3 F12 systems, it reliably dumpeth the core for my
flowgraph. I’ll see if I can do a reduced
version (like what you’ve done) to provoke the same issue.


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

On 07/05/2010 12:03 PM, Tom R. wrote:


I created a signal, fft filter (ccc), and a file sink with a

The initial taps have length 27 and the new taps (taps1) have length
273. I also tried it with both complex in/out/taps and float
in/out/taps.

Is there something else that I’m missing?

Tom

Tom:

Just attached a tiny little file that generates the problem.

USRP source, FFT filter, null sink.

There’s a graphical control that controls the transition width of the
filter parameters. Changing that control
provokes the issue immediately.

On 07/05/2010 05:10 PM, Tom R. wrote:

Unfortunately, I don’t have a way to test this with a USRP right now,
so what I did was use a noise source and a throttle block instead of
the USRP source and it worked fine. Could you try it without the USRP
block and see what happens? It’d be strange if this was the cause, but
worth trying.

Tom

OK, will do!


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

On Mon, Jul 5, 2010 at 12:27 PM, Marcus D. Leech [email protected]
wrote:

at runtime.

tb.start()


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

Unfortunately, I don’t have a way to test this with a USRP right now,
so what I did was use a noise source and a throttle block instead of
the USRP source and it worked fine. Could you try it without the USRP
block and see what happens? It’d be strange if this was the cause, but
worth trying.

Tom

On 07/05/2010 05:10 PM, Tom R. wrote:

Tested it with a throttled random source–same deal.


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

On Mon, Jul 5, 2010 at 5:42 PM, Marcus D. Leech [email protected]
wrote:

Tested it with a throttled random source–same deal.


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org

Well crap, that doesn’t help at all then! Next question: what GCC does
F12 run? I’m on Ubuntu 10.04, which uses 4.4.3.

Also, I’m on vacation starting tomorrow for a week, so I won’t be any
more help for a while.

Tom

On 07/06/2010 10:52 PM, Tom R. wrote:

Well crap, that doesn’t help at all then! Next question: what GCC does
F12 run? I’m on Ubuntu 10.04, which uses 4.4.3.

Also, I’m on vacation starting tomorrow for a week, so I won’t be any
more help for a while.

Tom

gcc 4.4.3


Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org