Re: double free or corruption error when two instances of an OOT block using fftw is called in GRC

[Grace Yeung]

Thank you Marcus for taking the time to look through the backtrace 
error. ApplyFilterBank simply calls ForwardFT to perform the FFT and 
does not access the plan. It only uses the FFT output. I had to destroy 
the plan each time because I noticed memory was consistently growing 
when gnuradio was running the flowgraph. After adding the destroy_plan 
memory stops growing. Hope this makes sense. Thank you.

Grace



On 4/21/23 07:11, Marcus Müller wrote:
> Hi Grace,
>
> reading this backtrace, the error happens in
>
> #29 0x00007fffe99b04d5 in 
> gr::customModule::probeExtract_impl::ApplyFilterBank
>
> So, that's where you need to look, not sure whether the other code you 
> shared helps.
>
> But reading your other code: you seem to be making an FFT plan and 
> destroying it *every single time you do an FFT*. That's a terrible 
> idea – planning an FFT typically takes much longer than doing an FFT, 
> even a really badly implemented one.
> You also make a local array of plans, just to put that single plan in, 
> then destroy it.
> This indicates you've got a logical bug in your thinking about C++ 
> scoping and lifetimes. If I had to take a wild guess, you're trying to 
> access a plan that does no longer exist in your ApplyFilterBank.
>
> Best regards,
> Marcus
>
> On 19.04.23 20:18, Grace Yeung wrote:
> > After some debugging, it appears grc is breaking inside of calls to 
> > fftw (see below). I am simply trying to use fftw to perform a simple 
> > FFT transform (forward/backward). Is there anything special I need to 
> > watch out for when using fftw with gnuradio? Any examples available? 
> > Any advice would be much appreciated. Thanks!
> >
> > Backtracing shows the crash happens in an fftw3f library function 
> > used in the code...
> >
> > (gdb) bt
> > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
> > #1 <https://github.com/gnuradio/gnuradio/pull/1>0x00007ffff7dd1859 in 
> > __GI_abort () at abort.c:79
> > #2 <https://github.com/gnuradio/gnuradio/pull/2>0x00007ffff7e3c26e in 
> > __libc_message (action=action@entry=do_abort, 
> > fmt=fmt@entry=0x7ffff7f66298 "%s\n") at 
> > ../sysdeps/posix/libc_fatal.c:155
> > #3 <https://github.com/gnuradio/gnuradio/pull/3>0x00007ffff7e442fc in 
> > malloc_printerr (str=str@entry=0x7ffff7f68628 "double free or 
> > corruption (fasttop)") at malloc.c:5347
> > #4 <https://github.com/gnuradio/gnuradio/pull/4>0x00007ffff7e45c65 in 
> > _int_free (av=0x7fffac000020, p=0x7fffac55a8d0, have_lock=0) at 
> > malloc.c:4266
> > #5 <https://github.com/gnuradio/gnuradio/pull/5>0x00007fffefe830d9 in 
> > ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #6 <https://github.com/gnuradio/gnuradio/pull/6>0x00007fffefe83c44 in 
> > ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #7 <https://github.com/gnuradio/gnuradio/pull/7>0x00007fffefe83fc4 in 
> > fftwf_mkplan_d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #8 <https://github.com/gnuradio/gnuradio/pull/8>0x00007fffefe88e5d in 
> > ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #9 <https://github.com/gnuradio/gnuradio/pull/9>0x00007fffefe8380b in 
> > ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #10 <https://github.com/gnuradio/gnuradio/pull/10>0x00007fffefe83a03 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #11 <https://github.com/gnuradio/gnuradio/pull/11>0x00007fffefe83fc4 
> > in fftwf_mkplan_d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #12 <https://github.com/gnuradio/gnuradio/pull/12>0x00007fffefe8d95c 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #13 <https://github.com/gnuradio/gnuradio/pull/13>0x00007fffefe8380b 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #14 <https://github.com/gnuradio/gnuradio/pull/14>0x00007fffefe83a03 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #15 <https://github.com/gnuradio/gnuradio/pull/15>0x00007fffefe83fc4 
> > in fftwf_mkplan_d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #16 <https://github.com/gnuradio/gnuradio/pull/16>0x00007fffefe84043 
> > in fftwf_mkplan_f_d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #17 <https://github.com/gnuradio/gnuradio/pull/17>0x00007fffefe887a3 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #18 <https://github.com/gnuradio/gnuradio/pull/18>0x00007fffefe8380b 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #19 <https://github.com/gnuradio/gnuradio/pull/19>0x00007fffefe83a03 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #20 <https://github.com/gnuradio/gnuradio/pull/20>0x00007fffefe83fc4 
> > in fftwf_mkplan_d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #21 <https://github.com/gnuradio/gnuradio/pull/21>0x00007fffefe88e5d 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #22 <https://github.com/gnuradio/gnuradio/pull/22>0x00007fffefe8380b 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #23 <https://github.com/gnuradio/gnuradio/pull/23>0x00007fffefe83a03 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #24 <https://github.com/gnuradio/gnuradio/pull/24>0x00007fffeff4a583 
> > in ?? () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #25 <https://github.com/gnuradio/gnuradio/pull/25>0x00007fffeff4a758 
> > in fftwf_mkapiplan () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #26 <https://github.com/gnuradio/gnuradio/pull/26>0x00007fffeff4ddd7 
> > in fftwf_plan_many_dft () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #27 <https://github.com/gnuradio/gnuradio/pull/27>0x00007fffeff4d09b 
> > in fftwf_plan_dft () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #28 <https://github.com/gnuradio/gnuradio/pull/28>0x00007fffeff4cd9a 
> > in fftwf_plan_dft_1d () from /lib/x86_64-linux-gnu/libfftw3f.so.3
> > #29 <https://github.com/gnuradio/gnuradio/pull/29>0x00007fffe99b04d5 
> > in gr::customModule::probeExtract_impl::ApplyFilterBank(int, 
> > gr::customModule::probeExtract_impl::FilterBank, 
> > std::vector<std::complex, std::allocator<std::complex > >&, int, int, 
> > int, std::vector<float, std::allocator >&, int, int, int) ()
> > from 
> > /usr/local/lib/x86_64-linux-gnu/libgnuradio-customModule.so.1.0.0git
> > #30 <https://github.com/gnuradio/gnuradio/pull/30>0x00007fffe99b1f69 
> > in gr::customModule::probeExtract_impl::general_work(int, 
> > std::vector<int, std::allocator >&, std::vector<void const*, 
> > std::allocator<void const*> >&, std::vector<void*, 
> > std::allocator<void*> >&) () from 
> > /usr/local/lib/x86_64-linux-gnu/libgnuradio-customModule.so.1.0.0git
> > #31 <https://github.com/gnuradio/gnuradio/pull/31>0x00007ffff0799c03 
> > in gr::block_executor::run_one_iteration() () from 
> > /lib/x86_64-linux-gnu/libgnuradio-runtime.so.3.8.1
> > #32 <https://github.com/gnuradio/gnuradio/pull/32>0x00007ffff07ed59a 
> > in gr::tpb_thread_body::tpb_thread_body(boost::shared_ptrgr::block, 
> > boost::shared_ptrboost::barrier, int) ()
> > from /lib/x86_64-linux-gnu/libgnuradio-runtime.so.3.8.1
> > #33 <https://github.com/gnuradio/gnuradio/pull/33>0x00007ffff07dd818 
> > in ?? () from /lib/x86_64-linux-gnu/libgnuradio-runtime.so.3.8.1
> > #34 <https://github.com/gnuradio/gnuradio/pull/34>0x00007ffff07fc4e8 
> > in ?? () from /lib/x86_64-linux-gnu/libgnuradio-runtime.so.3.8.1
> > #35 <https://github.com/gnuradio/gnuradio/pull/35>0x00007ffff010343b 
> > in ?? () from /lib/x86_64-linux-gnu/libboost_thread.so.1.71.0
> > #36 
> > <https://github.com/gnuradio/gnuradio/issues/36>0x00007ffff7d94609 in 
> > start_thread (arg=) at pthread_create.c:477
> > #37 <https://github.com/gnuradio/gnuradio/pull/37>0x00007ffff7ece133 
> > in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
> >
> >
> >
> >
> > On 2/15/23 13:01, Grace Yeung wrote:
> > > Hi, I have a gnuradio out-of-tree block written in C++ that runs 
> > > fine in grc 3.8.1.0. But when I have two of them running 
> > > simultaneously in the flowgraph, grc crashes and gives me the error:
> > >
> > > double free or corruption (!prev)
> > >
> > > I am not using any free() functions. I use std::vector's in my code 
> > > which should handle dynamic memory allocation automatically. What 
> > > could be causing this error?
> > >
> > > The only other place I see in the code that deals with pointers is 
> > > the calling of "new" in the definition of the make function which 
> > > returns an sptr:
> > >       probeExtract::sptr
> > >       probeExtract::make(const char* filtName, const char* maskName, 
> > > int mlsrM, int numChan, int sampPerBit, int Tblock, int 
> > > edgeBufferSize, int structureType)
> > >       {
> > >           return gnuradio::get_initial_sptr
> > >           (new probeExtract_impl(filtName, maskName, mlsrM, numChan, 
> > > sampPerBit, Tblock, edgeBufferSize, structureType));
> > >       }
> > > I suppose I do not need to worry about free'ing the pointer which is 
> > > handled internally by python?
> > >
> > > After putting in some debugging statements, I see variations of 
> > > similar error such as:
> > > corrupted size vs. prev_size while consolidating
> > >
> > > Any advice would be greatly appreciated. Thank you.
> > >
> > > Grace
> >
> > --
> > Grace K. Yeung, MS
> > NorthWest Research Associates
> > 301 Webster Street
> > Monterey, CA 93940
> > grace@nwra.com
> > https://www.nwra.com

--
Grace K. Yeung, MS
NorthWest Research Associates
301 Webster Street
Monterey, CA 93940
grace@nwra.com
https://www.nwra.com

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