Postprocessing error: double free or corruption

[Syd]

On postprocessing an C113 with QS i get the following error:

> msieve -v -s a 10585388393121557532079359494442371726164092133953552745116518032657525331778057303161348445301120191368975687233

Msieve v. 1.40
Sat Mar 21 15:08:53 2009
random seeds: 4594c26b 66c31a21
factoring 10585388393121557532079359494442371726164092133953552745116518032657525331778057303161348445301120191368975687233 (113 digits)

searching for 15-digit factors
commencing quadratic sieve (113-digit input)
using multiplier of 1
using 32kb Intel Core sieve core
sieve interval: 62 blocks of size 32768
processing polynomials in batches of 4
using a sieve bound of 7885301 (266250 primes)
using large prime bound of 1182795150 (30 bits)
using double large prime bound of 21440610479710500 (46-55 bits)
using trial factoring cutoff of 55 bits
polynomial 'A' values have 15 factors
restarting with 38054 full and 2308636 partial relations

486805 relations (38054 full + 448751 combined from 2308636 partial), need 266346
sieving complete, commencing postprocessing
begin with 2346690 relations
reduce to 1018168 relations in 8 passes
attempting to read 1018168 relations
recovered 1018168 relations
recovered 951736 polynomials
freed 433740 duplicate relations
attempting to build 53065 cycles
found 53065 cycles in 5 passes
distribution of cycle lengths:
length 1 : 31015
length 2 : 11097
length 3 : 5681
length 4 : 2763
length 5 : 1383
length 6 : 591
length 7 : 296
length 9+: 239
largest cycle: 15 relations
matrix is 266250 x 53065 (10.7 MB) with weight 2370228 (44.67/col)
sparse part has weight 2370228 (44.67/col)
matrix is corrupt; skipping linear algebra
*** glibc detected *** msieve: double free or corruption (top): 0x0000000005a68550 ***
======= Backtrace: =========
/lib/libc.so.6[0x7f1a0322c948]
/lib/libc.so.6(cfree+0x76)[0x7f1a0322ea56]
msieve[0x40e1ea]
msieve[0x404e34]
msieve[0x402e27]
msieve[0x4036c2]
/lib/libc.so.6(__libc_start_main+0xe6)[0x7f1a031d71a6]
msieve[0x402bc9]
======= Memory map: ========
00400000-00465000 r-xp 00000000 21:44 270005981 /usr/bin/msieve
00664000-00665000 rw-p 00064000 21:44 270005981 /usr/bin/msieve
00c59000-09239000 rw-p 00c59000 00:00 0 [heap]
7f19e72a2000-7f19ee6d0000 rw-p 7f1a00461000 00:00 0
7f19f5d04000-7f19f7c17000 rw-p 7f1a0040d000 00:00 0
7f19fc000000-7f19fc021000 rw-p 7f19fc000000 00:00 0
7f19fc021000-7f1a00000000 ---p 7f19fc021000 00:00 0
7f1a02f8a000-7f1a02fa0000 r-xp 00000000 21:44 268435691 /lib/libgcc_s.so.1
7f1a02fa0000-7f1a031a0000 ---p 00016000 21:44 268435691 /lib/libgcc_s.so.1
7f1a031a0000-7f1a031a1000 rw-p 00016000 21:44 268435691 /lib/libgcc_s.so.1
7f1a031b9000-7f1a03303000 r-xp 00000000 21:44 268435918 /lib/libc-2.7.so
7f1a03303000-7f1a03502000 ---p 0014a000 21:44 268435918 /lib/libc-2.7.so
7f1a03502000-7f1a03505000 r--p 00149000 21:44 268435918 /lib/libc-2.7.so
7f1a03505000-7f1a03507000 rw-p 0014c000 21:44 268435918 /lib/libc-2.7.so
7f1a03507000-7f1a0350c000 rw-p 7f1a03507000 00:00 0
7f1a0350c000-7f1a03522000 r-xp 00000000 21:44 268435913 /lib/libpthread-2.7.so
7f1a03522000-7f1a03722000 ---p 00016000 21:44 268435913 /lib/libpthread-2.7.so
7f1a03722000-7f1a03724000 rw-p 00016000 21:44 268435913 /lib/libpthread-2.7.so
7f1a03724000-7f1a03728000 rw-p 7f1a03724000 00:00 0
7f1a03728000-7f1a03766000 r-xp 00000000 21:44 313739 /usr/lib/libgmp.so.3.4.2
7f1a03766000-7f1a03966000 ---p 0003e000 21:44 313739 /usr/lib/libgmp.so.3.4.2
7f1a03966000-7f1a03967000 rw-p 0003e000 21:44 313739 /usr/lib/libgmp.so.3.4.2
7f1a03967000-7f1a039ac000 r-xp 00000000 21:44 689837 /usr/lib/libecm.so.0.0.0
7f1a039ac000-7f1a03bab000 ---p 00045000 21:44 689837 /usr/lib/libecm.so.0.0.0
7f1a03bab000-7f1a03bb4000 rw-p 00044000 21:44 689837 /usr/lib/libecm.so.0.0.0
7f1a03bb4000-7f1a03c36000 r-xp 00000000 21:44 268435917 /lib/libm-2.7.so
7f1a03c36000-7f1a03e35000 ---p 00082000 21:44 268435917 /lib/libm-2.7.so
7f1a03e35000-7f1a03e37000 rw-p 00081000 21:44 268435917 /lib/libm-2.7.so
7f1a03e37000-7f1a03e53000 r-xp 00000000 21:44 268435922 /lib/ld-2.7.so
7f1a04034000-7f1a04037000 rw-p 7f1a04034000 00:00 0
7f1a0404e000-7f1a04052000 rw-p 7f1a0404e000 00:00 0
7f1a04052000-7f1a04054000 rw-p 0001b000 21:44 268435922 /lib/ld-2.7.so
7fff0c03e000-7fff0c053000 rw-p 7ffffffea000 00:00 0 [stack]
7fff0c1fe000-7fff0c1ff000 r-xp 7fff0c1fe000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Abgebrochen

The relations were sieved in 4 instances, finally merged together via

cat a{1,2,3,4} >> a

Any ideas whats wrong here?

Already tried with more or less relations, different set of relations, always the same error.

[jasonp]

Your run has a huge number of duplicate relations, and the QS code is not smart enough to realize that. With the duplicates removed, you do not have enough different relations to build a usable matrix. The double-free is a failed attempt to clean up afterwards. Do the workers use different random seeds?

[Syd]

Thank you jasonp!

The workers used different random seeds, but maybe my script duplicated some relations while merging them.