[Octave-bug-tracker] [bug #51950] Segfault during a sparse QR factorization

[Mike Miller]

Update of bug #51950 (project octave):

                Severity:              3 - Normal => 4 - Important          
                  Status:                    None => Confirmed              

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Follow-up Comment #4:

I can confirm also on the default branch (26ec2e264826). There are actually a
couple different ways this error can occur. I sometimes get a SIGSEGV, with a
backtrace like this (similar to the original, but with debug information):


#0  0x00007ff436f6e90f in _int_free (av=0x7ff43728eb00 <main_arena>,
p=0x555555bb5500, have_lock=0) at malloc.c:4052
#1  0x00007ff43299501e in cs_dl_free (address@hidden) at
../Source/cs_malloc.c:24
#2  0x00007ff43299354d in cs_dl_idone (p=0x555555bb3630, address@hidden,
w=0x555555bb5510, ok=1) at ../Source/cs_util.c:101
#3  0x00007ff432992539 in cs_dl_etree (address@hidden,
address@hidden) at ../Source/cs_etree.c:29
#4  0x00007ff43299483e in cs_dl_sqr (address@hidden,
address@hidden, address@hidden) at ../Source/cs_sqr.c:73
#5  0x00007ff4389a03e1 in
octave::math::sparse_qr<SparseMatrix>::sparse_qr_rep::sparse_qr_rep
(this=0x5555558bd490, a=..., order=0) at
../liboctave/numeric/sparse-qr.cc:203
#6  0x00007ff4389aae5e in octave::math::sparse_qr<SparseMatrix>::sparse_qr
(this=0x7fffffffa7c0, a=..., order=0) at
../liboctave/numeric/sparse-qr.cc:2133
#7  0x00007ff4258023cb in Fqr (args=..., nargout=2) at
../libinterp/dldfcn/qr.cc:295
...


Sometimes it throws a SIGSEGV with a backtrace looking like this:


#0  0x00007fcf1365218f in cs_dl_transpose (address@hidden,
address@hidden) at ../Source/cs_transpose.c:20
#1  0x00007fcf1364ed39 in cs_dl_counts (address@hidden,
parent=0x555555bb3630, address@hidden, address@hidden) at
../Source/cs_counts.c:27
#2  0x00007fcf13651866 in cs_dl_sqr (address@hidden,
address@hidden, address@hidden) at ../Source/cs_sqr.c:75
#3  0x00007fcf1965d3e1 in
octave::math::sparse_qr<SparseMatrix>::sparse_qr_rep::sparse_qr_rep
(this=0x5555558bd490, a=..., order=0) at
../liboctave/numeric/sparse-qr.cc:203
#4  0x00007fcf19667e5e in octave::math::sparse_qr<SparseMatrix>::sparse_qr
(this=0x7fffffffa7c0, a=..., order=0) at
../liboctave/numeric/sparse-qr.cc:2133
#5  0x00007fcf064bf3cb in Fqr (args=..., nargout=2) at
../libinterp/dldfcn/qr.cc:295
...


And sometimes it exits with a SIGABRT with a backtrace looking like this:


#1  0x00007f57a8c0f42a in __GI_abort () at abort.c:89
#2  0x00007f57a8c4bc00 in __libc_message (address@hidden,
address@hidden "*** Error in `%s': %s: 0x%s ***\n") at
../sysdeps/posix/libc_fatal.c:175
#3  0x00007f57a8c51fc6 in malloc_printerr (action=3, str=0x7f57a8d3d9c9
"realloc(): invalid next size", ptr=<optimized out>, ar_ptr=<optimized out>)
at malloc.c:5049
#4  0x00007f57a8c5513c in _int_realloc (address@hidden
<main_arena>, address@hidden, address@hidden,
address@hidden) at malloc.c:4290
#5  0x00007f57a8c56719 in __GI___libc_realloc (oldmem=0x555555c307a0,
bytes=27080) at malloc.c:3083
#6  0x00007f57a4679051 in cs_dl_realloc (p=0x555555c307a0, address@hidden,
address@hidden, address@hidden) at ../Source/cs_malloc.c:32
#7  0x00007f57a46771d9 in cs_dl_sprealloc (address@hidden,
nzmax=3385, address@hidden) at ../Source/cs_util.c:26
#8  0x00007f57a46766c5 in cs_dl_fkeep (A=0x555555c04980,
address@hidden <cs_nonzero>, address@hidden) at
../Source/cs_fkeep.c:23
#9  0x00007f57a46761de in cs_dl_dropzeros (A=<optimized out>) at
../Source/cs_dropzeros.c:8
#10 0x00007f57aa6849b4 in
octave::math::sparse_qr<SparseMatrix>::sparse_qr_rep::R (this=0x5555558bd490,
address@hidden) at ../liboctave/numeric/sparse-qr.cc:281
#11 0x00007f57aa68ef8f in octave::math::sparse_qr<SparseMatrix>::R
(address@hidden, address@hidden) at
../liboctave/numeric/sparse-qr.cc:2198
#12 0x00007f57974e6413 in Fqr (args=..., nargout=<optimized out>) at
../libinterp/dldfcn/qr.cc:305
...



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