Hi Devin, I don't think it's a kernel problem – all your calculations happen in userland, and the kernel has not much to say with respect to the instructions used.
The most common reason for this kind of misbehaviour is in fact a problem with how the application (in this case, your GNU Radio application's block) calls into the library function (in this case the VOLK dot product). Is it possible that for some reason, GNU Radio used a previous version of VOLK when you linked it, and then the new version of VOLK was installed? Best regards, Marcus On 12/01/2016 05:23 PM, devin kelly wrote: > Hello, > > I'm having a problem with the above VOLK function segfaulting. I > don't think I'm passing any incorrect values to VOLK. My problem > could be that I'm on RHEL7 with (obviously) an older kernel: > > $ uname -a > Linux 520842-mitll 3.10.0-327.10.1.el7.x86_64 #1 SMP Sat Jan 23 > 04:54:55 EST 2016 x86_64 x86_64 x86_64 GNU/Linux > > I'm on VOLK 1.3 and GR 3.7.10.1. > > it segfaults here: > https://github.com/gnuradio/volk/blob/maint/kernels/volk/volk_32fc_32f_dot_prod_32fc.h#L119 > It looks like aPtr (0x7fea5c3014c0) is somehow not valid. GR passes > this pointer to VOLK so maybe it's a GR problem? > > I've copied the output of a GDB session and my CPU info below. > > Thanks for any help, > Devin > > > > Program terminated with signal 11, Segmentation fault. > #0 0x00007fea7b1bd8b7 in _mm256_load_ps (__P=0x7fea5c3014c0) at > /usr/lib/gcc/x86_64-redhat-linux/4.8.5/include/avxintrin.h:835 > 835 return *(__m256 *)__P; > Missing separate debuginfos, use: debuginfo-install > python-2.7.5-48.el7.x86_64 > (gdb) bt > #0 0x00007fea7b1bd8b7 in volk_32fc_32f_dot_prod_32fc_a_avx > (__P=0x7fea5c3014c0) at > /usr/lib/gcc/x86_64-redhat-linux/4.8.5/include/avxintrin.h:835 > #1 0x00007fea7b1bd8b7 in volk_32fc_32f_dot_prod_32fc_a_avx > (result=0x3665160, input=0x7fea5c3014c0, taps=0x3671a00, > num_points=47) at > /local_disk/gr_3.7.10.1_src/volk/kernels/volk/volk_32fc_32f_dot_prod_32fc.h:119 > #2 0x00007fea6661d88f in > gr::filter::kernel::fir_filter_ccf::filter(std::complex<float> const*) > () at /local_disk/gr_3.7.10.1/lib64/libgnuradio-filter-3.7.10.1.so.0.0.0 > #3 0x00007fea66c01d01 in > gr::digital::pfb_clock_sync_ccf_impl::general_work(int, > std::vector<int, std::allocator<int> >&, std::vector<void const*, > std::allocator<void const*> >&, std::vector<void*, > std::allocator<void*> >&) () > at /local_disk/gr_3.7.10.1/lib64/libgnuradio-digital-3.7.10.1.so.0.0.0 > #4 0x00007fea7b73fe10 in gr::block_executor::run_one_iteration() () > at /local_disk/gr_3.7.10.1/lib64/libgnuradio-runtime-3.7.10.1.so.0.0.0 > #5 0x00007fea7b781120 in > gr::tpb_thread_body::tpb_thread_body(boost::shared_ptr<gr::block>, > int) () at > /local_disk/gr_3.7.10.1/lib64/libgnuradio-runtime-3.7.10.1.so.0.0.0 > #6 0x00007fea7b774821 in > boost::detail::function::void_function_obj_invoker0<gr::thread::thread_body_wrapper<gr::tpb_container>, > void>::invoke(boost::detail::function::function_buffer&) () at > /local_disk/gr_3.7.10.1/lib64/libgnuradio-runtime-3.7.10.1.so.0.0.0 > #7 0x00007fea7b725ef0 in > boost::detail::thread_data<boost::function0<void> >::run() () at > /local_disk/gr_3.7.10.1/lib64/libgnuradio-runtime-3.7.10.1.so.0.0.0 > #8 0x00007fea7a22427a in thread_proxy () at > /lib64/libboost_thread-mt.so.1.53.0 > #9 0x00007fea960f3dc5 in start_thread () at /lib64/libpthread.so.0 > #10 0x00007fea9571973d in clone () at /lib64/libc.so.6 > (gdb) print __P > $1 = (const float *) 0x7fea5c3014c0 > (gdb) print *__P > Cannot access memory at address 0x7fea5c3014c0 > (gdb) print *(__m256 *)__P > Cannot access memory at address 0x7fea5c3014c0 > (gdb) f 1 > #1 volk_32fc_32f_dot_prod_32fc_a_avx (result=0x3665160, > input=0x7fea5c3014c0, taps=0x3671a00, num_points=47) at > /local_disk/gr_3.7.10.1_src/volk/kernels/volk/volk_32fc_32f_dot_prod_32fc.h:119 > 119 a0Val = _mm256_load_ps(aPtr); > (gdb) info locals > number = 0 > sixteenthPoints = 2 > res = {-1.30492652e+29, 0.0779444203} > realpt = 0x7fea57ffde50 > imagpt = 0x7fea57ffde54 > aPtr = 0x7fea5c3014c0 > bPtr = 0x3671a00 > a0Val = {-0.656753004, -0.658071458, -0.760932922, -0.762304127, > -0.869615495, -0.869560063, -0.887507021, -0.885902643} > a1Val = {-0.744178772, -0.742508531, -0.437728733, -0.437706977, > -0.0328192525, -0.0346645005, 0.376206338, 0.374125361} > a2Val = {0.711783648, 0.711464763, 0.931477308, 0.933318734, > 1.01744843, 1.01973152, 0.954917312, 0.955377996} > a3Val = {0.734342158, 0.732418418, 0.374049634, 0.371605545, > -0.0585254543, -0.0588675328, -0.461206883, -0.458686352} > b0Val = {0.0023738991, 0.0023738991, -0.00534401694, -0.00534401694, > 0.00242348039, 0.00242348039, 0.00727195293, 0.00727195293} > b1Val = {-0.0158917159, -0.0158917159, 0.00614725193, 0.00614725193, > 0.0485430211, 0.0485430211, -0.22138992, -0.22138992} > b2Val = {0, 0, 0.22138992, 0.22138992, -0.0485430211, -0.0485430211, > -0.00614725193, -0.00614725193} > b3Val = {0.0158917159, 0.0158917159, -0.00727195293, -0.00727195293, > -0.00242348039, -0.00242348039, 0.00534401694, 0.00534401694} > x0Val = {0.0023738991, -0.00534401694, 0.00242348039, 0.00727195293, > -0.0158917159, 0.00614725193, 0.0485430211, -0.22138992} > x1Val = {0, 0.22138992, -0.0485430211, -0.00614725193, 0.0158917159, > -0.00727195293, -0.00242348039, 0.00534401694} > x0loVal = {0.0023738991, 0.0023738991, -0.00534401694, -0.00534401694, > -0.0158917159, -0.0158917159, 0.00614725193, 0.00614725193} > x0hiVal = {0.00242348039, 0.00242348039, 0.00727195293, 0.00727195293, > 0.0485430211, 0.0485430211, -0.22138992, -0.22138992} > x1loVal = {0, 0, 0.22138992, 0.22138992, 0.0158917159, 0.0158917159, > -0.00727195293, -0.00727195293} > x1hiVal = {-0.0485430211, -0.0485430211, -0.00614725193, > -0.00614725193, -0.00242348039, -0.00242348039, 0.00534401694, > 0.00534401694} > c0Val = {-0.00155906542, -0.00156219525, 0.00406643841, 0.00407376606, > -0.00210749614, -0.0021073618, -0.00645390945, -0.0064422423} > c1Val = {0.0118262777, 0.011799735, -0.00269082887, -0.00269069499, > -0.00159314566, -0.00168271956, -0.0832882896, -0.082827583} > c2Val = {0, 0, 0.206219688, 0.206627354, -0.0493900217, -0.0495008491, > -0.00587011734, -0.00587294903} > c3Val = {0.0116699571, 0.0116393855, -0.00272007124, -0.00270229811, > 0.000141835291, 0.000142664314, -0.00246469746, -0.00245122775} > dotProdVal0 = {0, 0, 0, 0, 0, 0, 0, 0} > dotProdVal1 = {0, 0, 0, 0, 0, 0, 0, 0} > dotProdVal2 = {0, 0, 0, 0, 0, 0, 0, 0} > dotProdVal3 = {0, 0, 0, 0, 0, 0, 0, 0} > dotProductVector = {0.0218032673, 0.0217418969, 0.204074427, > 0.204509094, -0.0519821495, -0.0521854945, -0.0983558819, -0.097870864} > (gdb) print *aPtr > Cannot access memory at address 0x7fea5c3014c0 > > > > > $ lscpu > Architecture: x86_64 > CPU op-mode(s): 32-bit, 64-bit > Byte Order: Little Endian > CPU(s): 4 > On-line CPU(s) list: 0-3 > Thread(s) per core: 2 > Core(s) per socket: 2 > Socket(s): 1 > NUMA node(s): 1 > Vendor ID: GenuineIntel > CPU family: 6 > Model: 61 > Model name: Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz > Stepping: 4 > CPU MHz: 2038.664 > BogoMIPS: 5187.61 > Virtualization: VT-x > L1d cache: 32K > L1i cache: 32K > L2 cache: 256K > L3 cache: 4096K > NUMA node0 CPU(s): 0-3 > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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