Re: [Pkg-octave-devel] Bug#394982: octave2.9: Crashes on "x(:, :)=speye(1)"

[John W. Eaton]

On 24-Oct-2006, Rafael Laboissiere wrote:

| This works in my Debian etch system with octave2.9-2.9.9-3::
| 
|     octave2.9:1> speye (1);
|     octave2.9:2> x = speye (1);
| 
| But this don't:
| 
|     octave2.9:1> x (:, :) = speye (1);
|     panic: Segmentation fault -- stopping myself...
|     *** glibc detected *** malloc(): memory corruption (fast): 0x0904d970 ***
|     panic: attempted clean up apparently failed -- aborting...
|     Aborted
| 
| There is something weird with the indexing operation on the lefthand side
| when the variable being assigned is undefined.  For instance, this works:
| 
|     octave2.9:1> x = speye (1);
|     octave2.9:2> x (:, :) = speye (1);
| 
| At any rate, the malloc problem reported in the error message may indicate
| some Debian-specific bug.

It fails for me too, here:

  octave:1> x(:,:) = speye (1)
  *** glibc detected *** double free or corruption (out): 0x0000000001609490 ***

  Program received signal SIGABRT, Aborted.
  [Switching to Thread 47836373494320 (LWP 22077)]
  0x00002b81c54c607b in raise () from /lib/libc.so.6
  (gdb) where
  #0  0x00002b81c54c607b in raise () from /lib/libc.so.6
  #1  0x00002b81c54c784e in abort () from /lib/libc.so.6
  #2  0x00002b81c54fc639 in __fsetlocking () from /lib/libc.so.6
  #3  0x00002b81c55031a3 in mallopt () from /lib/libc.so.6
  #4  0x00002b81c550322e in free () from /lib/libc.so.6
  #5  0x00002b81c0d730d0 in ~SparseRep (this=0x1613d70) at 
/home/jwe/src/octave/liboctave/Sparse.h:101
  #6  0x00002b81c0d73124 in Sparse<double>::operator= (this=0x1474c30, 
address@hidden)
      at /home/jwe/src/octave/liboctave/Sparse.h:227
  #7  0x00002b81c178587c in assign<double, double> (address@hidden, 
address@hidden)
      at /home/jwe/src/octave/liboctave/Sparse.cc:2527
  #8  0x00002b81c0f6d1cf in octave_base_sparse<SparseMatrix>::assign 
(this=0x1474c20, address@hidden,
      address@hidden) at /home/jwe/src/octave/src/ov-base-sparse.cc:191
  #9  0x00002b81c1170b81 in oct_assignop_assign (address@hidden, 
address@hidden, address@hidden)
      at /home/jwe/src/octave/src/OPERATORS/op-sm-sm.cc:110
  #10 0x00002b81c0e719a2 in octave_base_value::numeric_assign (this=0x1474c20, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov-base.cc:924
  #11 0x00002b81c0f644c7 in octave_base_sparse<SparseMatrix>::subsasgn 
(this=0x1474c20, address@hidden,
      address@hidden, address@hidden) at 
/home/jwe/src/octave/src/ov-base-sparse.cc:148
  #12 0x00002b81c0eb070f in octave_value::subsasgn (this=0x7fffea17aad0, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov.cc:799
  #13 0x00002b81c0e75982 in octave_base_value::subsasgn (this=0x162e130, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov-base.cc:205
  #14 0x00002b81c0eb070f in octave_value::subsasgn (this=0x17345d0, 
address@hidden, address@hidden,
      address@hidden) at /home/jwe/src/octave/src/ov.cc:799
  #15 0x00002b81c0eb8563 in octave_value::assign (this=0x17345d0, 
op=octave_value::op_asn_eq,
      address@hidden, address@hidden, address@hidden) at 
/home/jwe/src/octave/src/ov.cc:846
  #16 0x00002b81c0e02c40 in octave_lvalue::assign (this=0x7fffea17ae60, 
op=octave_value::op_asn_eq,
      address@hidden) at /home/jwe/src/octave/src/oct-lvalue.cc:38
  #17 0x00002b81c0f6ff33 in tree_simple_assignment::rvalue (this=0x17f8f00)
      at /home/jwe/src/octave/src/pt-assign.cc:106
  #18 0x00002b81c0f70752 in tree_simple_assignment::rvalue (this=0x17f8f00, 
nargout=0)
      at /home/jwe/src/octave/src/pt-assign.cc:64
  #19 0x00002b81c0f94e69 in tree_statement::eval (this=0x17f7cd0, silent=false, 
nargout=0,
      in_function_body=false) at /home/jwe/src/octave/src/pt-stmt.cc:133
  #20 0x00002b81c0f950fa in tree_statement_list::eval (this=0x1638850, 
silent=false, nargout=0)
      at /home/jwe/src/octave/src/pt-stmt.cc:190
  #21 0x00002b81c0e55024 in main_loop () at 
/home/jwe/src/octave/src/toplev.cc:225
  #22 0x00002b81c0e000b2 in octave_main (argc=3, argv=0x7fffea17b638, 
embedded=0)
      at /home/jwe/src/octave/src/octave.cc:766
  #23 0x00002b81c54b34ca in __libc_start_main () from /lib/libc.so.6
  #24 0x000000000040078a in _start () at ../sysdeps/x86_64/elf/start.S:113

Also, this fails:

  octave:1> x(:,:) = sprand (10, 10, 0.1)

  Program received signal SIGSEGV, Segmentation fault.
  [Switching to Thread 47019963046448 (LWP 22097)]
  0x00002ac3ab9d9691 in assign<double, double> (address@hidden, address@hidden)
      at /home/jwe/src/octave/liboctave/Sparse.cc:2663
  2663                                          pp = (++ppp < ppi ? 
lhs.ridx(lhs.cidx(j)+ppp) : new_nr);
  (gdb) where
  #0  0x00002ac3ab9d9691 in assign<double, double> (address@hidden, 
address@hidden)
      at /home/jwe/src/octave/liboctave/Sparse.cc:2663
  #1  0x00002ac3ab1c01cf in octave_base_sparse<SparseMatrix>::assign 
(this=0x1474c20, address@hidden,
      address@hidden) at /home/jwe/src/octave/src/ov-base-sparse.cc:191
  #2  0x00002ac3ab3c3b81 in oct_assignop_assign (address@hidden, 
address@hidden, address@hidden)
      at /home/jwe/src/octave/src/OPERATORS/op-sm-sm.cc:110
  #3  0x00002ac3ab0c49a2 in octave_base_value::numeric_assign (this=0x1474c20, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov-base.cc:924
  #4  0x00002ac3ab1b74c7 in octave_base_sparse<SparseMatrix>::subsasgn 
(this=0x1474c20, address@hidden,
      address@hidden, address@hidden) at 
/home/jwe/src/octave/src/ov-base-sparse.cc:148
  #5  0x00002ac3ab10370f in octave_value::subsasgn (this=0x7ffffff2a880, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov.cc:799
  #6  0x00002ac3ab0c8982 in octave_base_value::subsasgn (this=0x1639300, 
address@hidden,
      address@hidden, address@hidden) at /home/jwe/src/octave/src/ov-base.cc:205
  #7  0x00002ac3ab10370f in octave_value::subsasgn (this=0x17345d0, 
address@hidden, address@hidden,
      address@hidden) at /home/jwe/src/octave/src/ov.cc:799
  #8  0x00002ac3ab10b563 in octave_value::assign (this=0x17345d0, 
op=octave_value::op_asn_eq,
      address@hidden, address@hidden, address@hidden) at 
/home/jwe/src/octave/src/ov.cc:846
  #9  0x00002ac3ab055c40 in octave_lvalue::assign (this=0x7ffffff2ac10, 
op=octave_value::op_asn_eq,
      address@hidden) at /home/jwe/src/octave/src/oct-lvalue.cc:38
  #10 0x00002ac3ab1c2f33 in tree_simple_assignment::rvalue (this=0x17f8e00)
      at /home/jwe/src/octave/src/pt-assign.cc:106
  #11 0x00002ac3ab1c3752 in tree_simple_assignment::rvalue (this=0x17f8e00, 
nargout=0)
      at /home/jwe/src/octave/src/pt-assign.cc:64
  #12 0x00002ac3ab1e7e69 in tree_statement::eval (this=0x17f8f10, silent=false, 
nargout=0,
      in_function_body=false) at /home/jwe/src/octave/src/pt-stmt.cc:133
  #13 0x00002ac3ab1e80fa in tree_statement_list::eval (this=0x1610af0, 
silent=false, nargout=0)
      at /home/jwe/src/octave/src/pt-stmt.cc:190
  #14 0x00002ac3ab0a8024 in main_loop () at 
/home/jwe/src/octave/src/toplev.cc:225
  #15 0x00002ac3ab0530b2 in octave_main (argc=3, argv=0x7ffffff2b3e8, 
embedded=0)
      at /home/jwe/src/octave/src/octave.cc:766
  #16 0x00002ac3af7064ca in __libc_start_main () from /lib/libc.so.6
  #17 0x000000000040078a in _start () at ../sysdeps/x86_64/elf/start.S:113
  (gdb) list
  2658                                      else
  2659                                        {
  2660                                          stmp.data(kk) =
  2661                                            lhs.data(lhs.cidx(j)+ppp);
  2662                                          stmp.ridx(kk++) = pp;
  2663                                          pp = (++ppp < ppi ? 
lhs.ridx(lhs.cidx(j)+ppp) : new_nr);
  2664                                        }
  2665                                    }
  2666                                  if (++jji < m)
  2667                                    jj = idx_j.elem(jji);
  (gdb)


If the value on the RHS is already a sparse matrix of the right size,
there is no crash:

  octave:2> x = speye (10);
  octave:3> x(:,:) = sprand (10, 10, 0.1)
  x =

  Compressed Column Sparse (rows = 10, cols = 10, nnz = 10)

    (10, 2) ->  0.68794
    (9, 3) ->  0.62723
    (5, 6) ->  0.89773
    (10, 6) ->  0.15447
    (3, 7) ->  0.69555
    (3, 8) ->  0.10861
    (5, 8) ->  0.39224
    (8, 8) ->  0.64466
    (6, 9) ->  0.57941
    (5, 10) ->  0.51256

David, I don't really understand the code here, so if there is
something I can do to help debug this, let me know.

Thanks,

jwe