crash on __gmpz_init

Mon Jan 22 11:19:58 CET 2024

Hi Marc,
thanks for the quick answer on the first case.
But the issue is also present if I use malloc in C.
Bests
Igor P

On 22/01/24 11:02, Marc Glisse wrote:
> Hello,
> 
>    mpz_class M[LINES][COLS];
> 
> you are trying to put an array with millions of elements on the stack, 
> so the stack overflows. Very large arrays need to be allocated on the 
> heap in C++ (new, malloc, or some wrapper like std::vector).
> 
> On Mon, 22 Jan 2024, igor pesando - Dept of Physics, University of 
> Torino wrote:
> 
>> Hi *,
>> first of all thanks for your work.
>>
>> The programs are attached as required.
>>
>>
>> Best regards
>> Igor Pesando
>>
>> *********************************************************************
>>
>> The issue I have is that the allocation in of a matrix in c++ crashes
>> the program with SEGFAULT if the dimension are big enough.
>>
>> LINES and COLS are the number of lines and columns of a matrix.
>>
>>
>> g++ -DLINES=5000 -DCOLS=5000 test2_mem.cpp -lgmp -lgmpxx -o t_500x500
>> ./t_500x500
>> version6.2.1; bits/limb 64
>>
>>
>> g++ -DLINES=5000 -DCOLS=5000 test2_mem.cpp -lgmp -lgmpxx -o t_5000x5000
>> ./t_5000x5000
>> Segmentation fault (core dumped)
>>
>>
>> The issue is not that my computer has not enough memory.
>> In facts when I run the corresponding program in C it crashes in 
>> __gmpz_init
>> BUT it does not crash when I allocate twice as much memory (SC is the 
>> scaling factor for the allocated memory).
>>
>>
>> gcc -DLINES=500 -DCOLS=500 -DSC=1 test2_mem.c -lgmp  -o tc_500x500
>> ./tc_500x500
>> allocating 250000; size=16
>>
>>
>> gcc -DLINES=5000 -DCOLS=5000 -DSC=1 test2_mem.c -lgmp  -o tc_5000x5000
>> igor at igor7a:~/tex/LCSFT/cpp/BUG_GMP_20240122$ ./tc_5000x5000
>> allocating 25000000; size=16
>>
>>
>> gcc -DLINES=7000 -DCOLS=5000 -DSC=1 test2_mem.c -lgmp  -o tc_7000x5000
>> ./tc_7000x5000 -g
>> allocating 35000000; size=16
>> Segmentation fault (core dumped)
>>
>>
>> Twice as much memory
>> gcc -DLINES=7000 -DCOLS=5000 -DSC=2 test2_mem.c -lgmp  -o tc_7000x5000x2
>> ./tc_7000x5000x2
>> allocating 35000000; size=16
>>
>>
>> **********************************************************************
>> GDB
>>
>> gdb ./tc_7000x5000
>>
>> (gdb) r
>> Starting program: /home/igor/tex/LCSFT/cpp/BUG_GMP_20240122/tc_7000x5000
>> [Thread debugging using libthread_db enabled]
>> Using host libthread_db library 
>> "/lib/x86_64-linux-gnu/libthread_db.so.1".
>> allocating 35000000; size=16
>>
>> Program received signal SIGSEGV, Segmentation fault.
>> 0x00007ffff7f39c9b in __gmpz_init () from 
>> /lib/x86_64-linux-gnu/libgmp.so.10
>> (gdb) bt
>> #0  0x00007ffff7f39c9b in __gmpz_init () from 
>> /lib/x86_64-linux-gnu/libgmp.so.10
>> #1  0x00005555555552e9 in main () at test2_mem.c:28
>>
>> #1  0x00005555555552e9 in main () at test2_mem.c:28
>> (gdb) f 1
>> #1  0x00005555555552e9 in main () at test2_mem.c:28
>> 28          mpz_init( M[ lin*LINES +col] );
>> (gdb) p lin
>> $1 = 5000
>> (gdb) p col
>> $2 = 63
>> (gdb)
>>
>> here lin is
>> ************************************************************
>>
>> Please include the following in any report:
>>
>> ************************************************************
>> The GMP version number, and if pre-packaged or patched then say so.
>> gmp pre-packaged 6.2.1
>> gmp 6.3.0 from sources
>>
>>
>>
>>
>> ************************************************************
>>
>> A test program that makes it possible for us to reproduce the
>> bug. Include instructions on how to run the program.
>>
>> In attachment
>>
>> ************************************************************
>>    A description of what is wrong. If the results are incorrect, in
>>    what way. If you get a crash, say so.
>>
>>    If you get a crash, include a stack backtrace from the debugger if
>>    it’s informative (‘where’ in gdb, or ‘$C’ in adb).
>>
>> Above
>>
>> ************************************************************
>>    Please do not send core dumps, executables or straces.
>>
>> ************************************************************
>> The ‘configure’ options you used when building GMP, if any.
>>
>>    The output from ‘configure’, as printed to stdout, with any
>>    options used.
>>
>> ************************************************************
>>
>>    The name of the compiler and its version. For gcc, get the version 
>> with ‘gcc -v’, otherwise perhaps ‘what `which cc`’, or similar.
>>
>> gcc -v
>> Using built-in specs.
>> COLLECT_GCC=gcc
>> COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/11/lto-wrapper
>> OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
>> OFFLOAD_TARGET_DEFAULT=1
>> Target: x86_64-linux-gnu
>> Configured with: ../src/configure -v --with-pkgversion='Ubuntu 
>> 11.4.0-1ubuntu1~22.04' 
>> --with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs 
>> --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 
>> --prefix=/usr --with-gcc-major-version-only --program-suffix=-11 
>> --program-prefix=x86_64-linux-gnu- --enable-shared 
>> --enable-linker-build-id --libexecdir=/usr/lib 
>> --without-included-gettext --enable-threads=posix --libdir=/usr/lib 
>> --enable-nls --enable-bootstrap --enable-clocale=gnu 
>> --enable-libstdcxx-debug --enable-libstdcxx-time=yes 
>> --with-default-libstdcxx-abi=new --enable-gnu-unique-object 
>> --disable-vtable-verify --enable-plugin --enable-default-pie 
>> --with-system-zlib --enable-libphobos-checking=release 
>> --with-target-system-zlib=auto --enable-objc-gc=auto 
>> --enable-multiarch --disable-werror --enable-cet --with-arch-32=i686 
>> --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib 
>> --with-tune=generic 
>> --enable-offload-targets=nvptx-none=/build/gcc-11-XeT9lY/gcc-11-11.4.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-11-XeT9lY/gcc-11-11.4.0/debian/tmp-gcn/usr --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu --with-build-config=bootstrap-lto-lean --enable-link-serialization=2
>> Thread model: posix
>> Supported LTO compression algorithms: zlib zstd
>> gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
>>
>>
>> ************************************************************
>>
>> The output from running ‘uname -a’.
>>
>> Linux igor7a 6.5.0-14-generic #14~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC
>> Mon Nov 20 18:15:30 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
>>
>> ************************************************************
>>
>> The output from running ‘./config.guess’, and from running 
>> ‘./configfsf.guess’ (might be the same).
>>
>>
>> ./config.guess
>> kabylake-pc-linux-gnu
>>
>> sh ./configfsf.guess
>> x86_64-pc-linux-gnu
> 