binaryArithmetic: Segmentation Fault

[patrick-schwarz]

Contact: patrick.schwarz@student.tugraz.at
Environment:

• using the Dockerfile provided but with 16 threads instead of 4
• os: windows 10
• docker version: v19.03.8
• cpu: i5-8600K

Problem:
After some additions i get a segmentation fault.
MultTwoNumbers and AddManyNumbers fail as well.

Code:

#include <helib/binaryArith.h>
#include <cmath>
#include <vector>
#include <NTL/BasicThreadPool.h>

int main(int argc, char *argv[]) {
    long bitSize = 6;
    long L = long(log(3)/log(2)*bitSize * 30); // for addition
    long p = 2; // Plaintext base [default=2], should be a prime number
    long m = 4095;
    long r = 1;
    long threadCount = 16;

    helib::Context context(m, p, r);
    buildModChain(context, L);

    helib::SecKey secKey(context);
    secKey.GenSecKey();
    addSome1DMatrices(secKey);
    addFrbMatrices(secKey);

    helib::PubKey &pubKey = secKey;
    long n_slots =  context.ea->size();

    std::vector<long> r_num(n_slots);
    for (long s = 0; s < n_slots; s++) {
        r_num[s] = NTL::RandomBits_long(bitSize);
    }

    NTL::Vec<helib::Ctxt> enca(NTL::INIT_SIZE,bitSize,helib::Ctxt(pubKey));
    for (long i = 0; i < bitSize; i++) {
        std::vector<long> ibits(n_slots);
        for (long s = 0; s < n_slots; s++)
            ibits[s] = (r_num[s] >> i) & 1;

        context.ea->encrypt(enca[i], pubKey, ibits);
    }

    NTL::SetNumThreads(threadCount);

    for (size_t i = 0; i < 1000; i++) {
        std::cout << std::to_string(NTL::AvailableThreads()) + "-" + std::to_string(i) + "\n" << std::flush;
        NTL::Vec<helib::Ctxt> sum, a, b;
        vecCopy(a, enca);
        vecCopy(b, enca);
        helib::CtPtrs_VecCt wsum(sum), wa(a), wb(b);

        //multTwoNumbers(wsum, wa, wb);
        addTwoNumbers(wsum, wa, wb);
    }

}

Error:

Process finished with exit code 139 (interrupted by signal 11: SIGSEGV)

Backtrace:

#0  0x000055bf35c0a0cc in helib::Ctxt::operator= (this=0x7, other=...) at /test/helib/include/helib/Ctxt.h:343
#1  0x00007f69ca9417e5 in helib::AddDAG::getCtxt (this=this@entry=0x7ffdfdf84920, node=node@entry=0x55bf37bf53f0, a=..., b=...) at /test/lib/HElib-master/src/binaryArith.cpp:418
#2  0x00007f69ca942bdd in helib::AddDAG::addCtxtFromNode (b=..., a=..., node=<optimized out>, c=..., this=0x7ffdfdf84920) at /test/lib/HElib-master/src/binaryArith.cpp:146
#3  helib::AddDAG::<lambda(long int, long int)>::operator() (last=2, first=<optimized out>, __closure=0x7ffdfdf84840) at /test/lib/HElib-master/src/binaryArith.cpp:346
#4  NTL::BasicThreadPool::ConcurrentTaskFct1<helib::AddDAG::apply(helib::CtPtrs&, const CtPtrs&, const CtPtrs&, long int)::<lambda(long int, long int)> >::run(long) (this=<optimized out>, index=<optimized out>) at /test/ntl/usr/local/include/NTL/BasicThreadPool.h:313
#5  0x000055bf35c0af5a in NTL::BasicThreadPool::runOneTask (task=warning: RTTI symbol not found for class 'NTL::BasicThreadPool::ConcurrentTaskFct1<helib::AddDAG::apply(helib::PtrVector<helib::Ctxt>&, helib::PtrVector<helib::Ctxt> const&, helib::PtrVector<helib::Ctxt> const&, long)::{lambda(long, long)#1}>'
0x7ffdfdf84860, index=1) at /test/ntl/usr/local/include/NTL/BasicThreadPool.h:392
#6  0x000055bf35c0b099 in NTL::BasicThreadPool::worker (localSignal=0x55bf386042b0) at /test/ntl/usr/local/include/NTL/BasicThreadPool.h:409
#7  0x000055bf35c0ef5d in std::__invoke_impl<void, void (*)(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*), NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*> (__f=@0x55bf386a9a10: 0x55bf35c0b042 <NTL::BasicThreadPool::worker(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*)>) at /usr/include/c++/7/bits/invoke.h:60
#8  0x000055bf35c0bed2 in std::__invoke<void (*)(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*), NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*> (__fn=@0x55bf386a9a10: 0x55bf35c0b042 <NTL::BasicThreadPool::worker(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*)>) at /usr/include/c++/7/bits/invoke.h:95
#9  0x000055bf35c1c82f in std::thread::_Invoker<std::tuple<void (*)(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*), NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*> >::_M_invoke<0ul, 1ul> (this=0x55bf386a9a08) at /usr/include/c++/7/thread:234
#10 0x000055bf35c1c632 in std::thread::_Invoker<std::tuple<void (*)(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*), NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*> >::operator() (this=0x55bf386a9a08) at /usr/include/c++/7/thread:243
#11 0x000055bf35c1bf8a in std::thread::_State_impl<std::thread::_Invoker<std::tuple<void (*)(NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*), NTL::BasicThreadPool::CompositeSignal<NTL::BasicThreadPool::ConcurrentTask*, long>*> > >::_M_run (this=0x55bf386a9a00) at /usr/include/c++/7/thread:186
#12 0x00007f69c9f2e6df in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#13 0x00007f69ca2016db in start_thread (arg=0x7f69c9248700) at pthread_create.c:463
#14 0x00007f69c95eb88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

[z0xi]

I also meet this problem after using some "addManyNumbers". Can anyone explain this?