Re: [Discuss-gnuradio] Segfault with volk on 32 bit AMD

[Frederick Stevens]

Well, at least for the moment, I have time (looking for employment, etc.).  I was considering trying it on another AMD 32 bit machine that I have sitting here with the same version of Slackware on it.  It may take me a day or two to bring it up to the same level of software as this one.  It's a uniprocessor motherboard but the same vintage of processor.

I am rebuilding gnuradio with your suggestions tonight and will let you know what gives when it is finished.  I'm also trying to get some RF hardware finished (my real area of expertise) so I will work this in between the rest of things.  Shouldn't be a problem though.

Cheers,

Fred
On 03/18/2012 04:31 PM, Tom Rondeau wrote:

On Fri, Mar 16, 2012 at 6:11 PM, Frederick Stevens <address@hidden> wrote:

Well, after a few restarts, here is my output.  I did a fresh pull from git because I was getting some errors with missing *.h files in gruel/src/swig or something like that.  Hope this helps!

RUN_VOLK_TESTS: volk_32fc_32f_multiply_32fc_a

Program received signal SIGSEGV, Segmentation fault.

0xb7edbb74 in volk_32fc_32f_multiply_32fc_a_generic (cVector=0xb7448008,
    aVector=0xb7768008, bVector=0xb78f8008, num_points=204600)
    at /home/fred/extras/gnuradio/gnuradio/volk/include/volk/volk_32fc_32f_multiply_32fc_a.h:74
74          *cPtr++ = (*aPtr++) * (*bPtr++);
(gdb) bt
#0  0xb7edbb74 in volk_32fc_32f_multiply_32fc_a_generic (cVector=0xb7448008,
    aVector=0xb7768008, bVector=0xb78f8008, num_points=204600)
    at /home/fred/extras/gnuradio/gnuradio/volk/include/volk/volk_32fc_32f_multiply_32fc_a.h:74

Alright, Fred, definitely something strange going on here. My only guess is that for some reason on your architecture/OS/whatever, something is being handled incorrectly and the buffers a, b, and c are not getting generated correctly, maybe something like it's not doubling the number of items for the complex data type (before this function test, there are 16ic, or complex shorts, being tested, but this is the first complex float test).

It's hard to tell if it's something about it being an AMD chip, 32-bit, Slackware version, gcc version, etc. And I don't have an AMD chip to test on, but I could load up a 32-bit Slackware VM at least.

How much work are you willing to put into this to help us nail this down?

If you can follow through the volk_profile test code, we can start outputting more debug info. To start with, I'd suggest going into volk/apps/volk_profile.cc and commenting out line 38, rebuild the application, and run this new volk_profile to see if it fails on any other kernels.

Thanks,

Tom