How to debug this crash?

Hi!

I've updated my system and after importing some old data I started getting
this message:

================================================================================
*** glibc detected *** postgres: godoy neo localhost(34476) SELECT: double free or corruption (out): 0x08494440 ***
======= Backtrace: =========
/lib/libc.so.6[0xb7b4f6e1]
/lib/libc.so.6(cfree+0x89)[0xb7b50d79]
/usr/lib/postgresql/plpython.so[0xb7ee3944]
/usr/lib/libpython2.5.so.1.0[0xb6b8d85a]
/usr/lib/libpython2.5.so.1.0(PyEval_EvalFrameEx+0x55dc)[0xb6be80ac]
/usr/lib/libpython2.5.so.1.0(PyEval_EvalCodeEx+0x7c4)[0xb6be9734]
/usr/lib/libpython2.5.so.1.0(PyEval_EvalCode+0x63)[0xb6be97b3]
/usr/lib/postgresql/plpython.so[0xb7ee4dfe]
/usr/lib/postgresql/plpython.so[0xb7ee5c97]
/usr/lib/postgresql/plpython.so(plpython_call_handler+0xf6)[0xb7ee7016]
postgres: godoy neo localhost(34476) SELECT(ExecMakeFunctionResult+0xec)[0x813813c]
postgres: godoy neo localhost(34476) SELECT(ExecProject+0x1c6)[0x81364e6]
postgres: godoy neo localhost(34476) SELECT(ExecNestLoop+0x127)[0x8143f37]
postgres: godoy neo localhost(34476) SELECT(ExecProcNode+0x130)[0x8135c40]
postgres: godoy neo localhost(34476) SELECT(ExecutorRun+0x30b)[0x8134f4b]
postgres: godoy neo localhost(34476) SELECT[0x81b8e50]
postgres: godoy neo localhost(34476) SELECT(PortalRun+0x198)[0x81b9aa8]
postgres: godoy neo localhost(34476) SELECT[0x81b58cc]
postgres: godoy neo localhost(34476) SELECT(PostgresMain+0x1481)[0x81b7491]
postgres: godoy neo localhost(34476) SELECT[0x818f92a]
postgres: godoy neo localhost(34476) SELECT(PostmasterMain+0xc5b)[0x8190aeb]
postgres: godoy neo localhost(34476) SELECT(main+0x249)[0x8153f89]
/lib/libc.so.6(__libc_start_main+0xdc)[0xb7b00f9c]
postgres: godoy neo localhost(34476) SELECT[0x8078ce1]
======= Memory map: ========
08048000-082d6000 r-xp 00000000 03:05 1037143 /usr/bin/postgres
082d6000-082e0000 rw-p 0028d000 03:05 1037143 /usr/bin/postgres
082e0000-08590000 rw-p 082e0000 00:00 0 [heap]
b6a00000-b6a21000 rw-p b6a00000 00:00 0
b6a21000-b6b00000 ---p b6a21000 00:00 0
b6b4e000-b6c3e000 r-xp 00000000 03:05 945257 /usr/lib/libpython2.5.so.1.0
b6c3e000-b6c64000 rw-p 000ef000 03:05 945257 /usr/lib/libpython2.5.so.1.0
b6c64000-b6cec000 rw-p b6c64000 00:00 0
b6cec000-b6d09000 r-xp 00000000 03:05 1404258 /usr/lib/postgresql/plpgsql.so
b6d09000-b6d0b000 rw-p 0001d000 03:05 1404258 /usr/lib/postgresql/plpgsql.so
b6d4c000-b6dcd000 rw-p b6d4c000 00:00 0
b6dcd000-b6dd7000 r-xp 00000000 03:05 651576 /lib/libgcc_s.so.1
b6dd7000-b6dd9000 rw-p 00009000 03:05 651576 /lib/libgcc_s.so.1
b6dd9000-b6dee000 r--p 00000000 03:05 1030633 /usr/share/locale/pt_BR/LC_MESSAGES/libc.mo
b6dee000-b6e50000 rw-p b6dee000 00:00 0
b6e50000-b784c000 rw-s 00000000 00:08 9666560 /SYSV0052e2c1 (deleted)
b784c000-b7892000 r--p 00000000 03:05 1037190 /usr/share/locale/pt_BR/LC_MESSAGES/postgres.mo
b7892000-b78c7000 r--s 00000000 03:05 392441 /var/run/nscd/db0rBNlN (deleted)
b78c7000-b7902000 r--p 00000000 03:05 1062284 /usr/lib/locale/pt_BR.utf8/LC_CTYPE
b7902000-b79d9000 r--p 00000000 03:05 1062285 /usr/lib/locale/pt_BR.utf8/LC_COLLATE
b79d9000-b7a0e000 r--s 00000000 03:05 392440 /var/run/nscd/group
b7a0e000-b7a43000 r--s 00000000 03:05 392433 /var/run/nscd/passwd
b7a43000-b7a45000 rw-p b7a43000 00:00 0
b7a45000-b7a59000 r-xp 00000000 03:05 651558 /lib/libpthread-2.5.so
b7a59000-b7a5b000 rw-p 00013000 03:05 651558 /lib/libpthread-2.5.so
b7a5b000-b7a5d000 rw-p b7a5b000 00:00 0
b7a5d000-b7a98000 r-xp 00000000 03:05 651584 /lib/libncurses.so.5.5
b7a98000-b7a9f000 r--p 0003a000 03:05 651584 /lib/libncurses.so.5.5
b7a9f000-b7aa4000 rw-p 00041000 03:05 651584 /lib/libncurses.so.5.5
b7aa4000-b7aab000 r-xp 00000000 03:05 1032787 /usr/lib/libkrb5support.so.0.1
b7aab000-b7aad000 rw-p 00006000 03:05 1032787 /usr/lib/libkrb5support.so.0.1
b7aad000-b7aae000 rw-p b7aad000 00:00 0
b7aae000-b7ad2000 r-xp 00000000 03:05 1032775 /usr/lib/libk5crypto.so.3.0
b7ad2000-b7ad4000 rw-p 00023000 03:05 1032775 /usr/lib/libk5crypto.so.3.0
b7ad4000-b7ae5000 r-xp 00000000 03:05 651569 /lib/libaudit.so.0.0.0
b7ae5000-b7ae7000 rw-p 00010000 03
================================================================================

(the last line ends like that already... I believe it is missing
information...)

This happens when running this view:

================================================================================
CREATE OR REPLACE VIEW neolab.v_resultado_amostra_analise AS
SELECT vrr.amostra_analise_id AS id, vrr.id AS amostra_id,
ar.liberado AS is_liberado, ar.alterado_em,
an.metodologia, an.ibmp, an.valores_referencia, an.nome AS analise,
neolab.f_v_formata_valor_resultado(
(SELECT o_resultado
FROM neolab.f_v_resultado_amostra_analise(vrr.amostra_analise_id)),
an.id) AS resultado,
(SELECT o_is_limite_quantificacao
FROM neolab.f_v_resultado_amostra_analise(vrr.amostra_analise_id))
AS is_limite_quantificacao
FROM neolab.v_resultados_resumo vrr
LEFT JOIN neolab.amostras_resultados ar ON ar.amostra_analise_id = vrr.amostra_analise_id
JOIN neolab.amostras_analises aa ON aa.id = vrr.amostra_analise_id
JOIN neolab.analises an ON an.id = aa.analise_id;
================================================================================

where the function called is:

================================================================================
CREATE OR REPLACE FUNCTION neolab.f_v_formata_valor_resultado(
p_resultado FLOAT, p_analise_id INTEGER,
OUT o_resultado TEXT)
AS $_$
p_resultado = args[0]
p_analise_id = args[1]

precisao=plpy.execute('''
SELECT precisao FROM neolab.analises
WHERE id=%s''' % p_analise_id)
unidade=plpy.execute('''
SELECT u.simbolo FROM neolab.unidades u
JOIN neolab.analises a ON a.unidade_relatorio_id = u.id
WHERE a.id = %s''' % p_analise_id)
formato='%%.%sf %s' % (precisao[0]['precisao'], unidade[0]['simbolo'])
return ((formato % p_resultado).replace('.', ','))
$_$ LANGUAGE plpythonu STABLE STRICT;

-- -----------------------------------------------------------------------------
-- Sample output:
-- -----------------------------------------------------------------------------
--
-- neo=# select * from neolab.f_v_formata_valor_resultado(3.23456, 53);
-- o_resultado
-- ----------------
-- 3,23 mg/g crea
-- (1 registro)
--
-- neo=# select * from neolab.f_v_formata_valor_resultado(3.23456, 59);
-- o_resultado
-- -------------
-- 3,23 g/L
-- (1 registro)

CREATE OR REPLACE FUNCTION neolab.f_v_resultado_amostra_analise(
p_amostra_analise_id INTEGER,
OUT o_resultado FLOAT, OUT o_is_limite_quantificacao BOOL) AS $_$
DECLARE
w_resultado FLOAT;
w_analise_id INTEGER;
w_limite_quantificacao FLOAT;
BEGIN
o_is_limite_quantificacao:=FALSE;
w_resultado:=resultado_calculado FROM neolab.amostras_resultados
WHERE amostra_analise_id=p_amostra_analise_id;
w_analise_id:=analise_id FROM neolab.amostras_analises
WHERE id=p_amostra_analise_id;
w_limite_quantificacao:=limite_quantificacao FROM neolab.analises
WHERE id=w_analise_id;
IF w_resultado < w_limite_quantificacao THEN
o_is_limite_quantificacao:=TRUE;
w_resultado:=w_limite_quantificacao;
END IF;
o_resultado:=w_resultado;
END;
$_$ LANGUAGE plpgsql STRICT STABLE;

================================================================================

Sometimes I can run (repeatedly) the offending view, but when it crashes I
have to restart the machine to be able to run it again.

On psql I get:

================================================================================
neo=# select * from neolab.v_resultado_amostra_analise ;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!> \q
================================================================================

This is with:

OpenSuSE 10.2
postgresql-server-8.1.5-13
postgresql-libs-8.1.5-13
postgresql-docs-8.1.5-13
postgresql-devel-8.1.5-13
postgresql-8.1.5-13
postgresql-pl-8.1.5-15

jupiter:/var/lib/pgsql/data/pg_log # psql -V
psql (PostgreSQL) 8.1.5
contains support for command-line editing

Linux jupiter 2.6.18.2-34-default #1 SMP Mon Nov 27 11:46:27 UTC 2006 i686 i686 i386 GNU/Linux

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Mobile Intel(R) Pentium(R) 4 CPU 3.06GHz
stepping : 1
cpu MHz : 1867.000
cache size : 1024 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc up pni monitor ds_cpl est tm2 cid xtpr
bogomips : 6137.03

(HT is disabled)

So, my doubt is: where do I start debugging that? :-)

Thanks for any help,
--
Jorge Godoy <jgodoy(at)gmail(dot)com>