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Thread: BUG #2766: erratic segfault in libpq/DBD::Pg

BUG #2766: erratic segfault in libpq/DBD::Pg

From
"Karl DeBieechop"
Date:
The following bug has been logged online:

Bug reference:      2766
Logged by:          Karl DeBieechop
Email address:      kdebisschop@alert.infoplease.com
PostgreSQL version: 8.1.4
Operating system:   Fedora 5
Description:        erratic segfault in libpq/DBD::Pg
Details:

error is completely erratic - will work 10 times, then fail. or fail 10 time
then work. So I have not been able to find a reporduacble test case. But
here's a trace:

*** glibc detected *** /usr/bin/perl: realloc(): invalid pointer: 0x091c2f94
***
======= Backtrace: =========
/lib/libc.so.6(__libc_realloc+0x302)[0x77039b]
/usr/lib/libpq.so.4(enlargePQExpBuffer+0x68)[0x8c7c48]
/usr/lib/libpq.so.4(printfPQExpBuffer+0x7f)[0x8c7e8f]
/usr/lib/libpq.so.4(PQgetResult+0xea)[0x8bf54a]
/usr/lib/libpq.so.4[0x8bf6c8]
/usr/lib/libpq.so.4(PQexec+0x27)[0x8bf967]
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so[0
x89d5c9]
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so[0
x8a051f]
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so(d
bd_st_destroy+0x180)[0x8a0b90]
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so(X
S_DBD__Pg__st_DESTROY+0x2c2)[0x898592]
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBI/DBI.so(XS_
DBI_dispatch+0x22c8)[0x121128]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(Perl_pp_entersu
b+0x40d)[0x3c0c01d]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so[0x3ba5ce1]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(Perl_call_sv+0x
5e6)[0x3baa4d6]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(Perl_sv_clear+0
x84)[0x3c108f4]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(Perl_sv_free+0x
85)[0x3c11155]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so[0x3c116fe]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so[0x3c0e7d0]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(Perl_sv_clean_o
bjs+0x3a)[0x3c0e83a]
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so(perl_destruct+0
x103f)[0x3bac3bf]
/usr/bin/perl(main+0xe7)[0x80492f7]
/lib/libc.so.6(__libc_start_main+0xdc)[0x71e4e4]
/usr/bin/perl[0x8049181]
======= Memory map: ========
00111000-0012e000 r-xp 00000000 08:05 475601
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBI/DBI.so
0012e000-0012f000 rwxp 0001c000 08:05 475601
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBI/DBI.so
0012f000-00138000 r-xp 00000000 08:05 312384
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/List/Util/Util.so
00138000-00139000 rwxp 00008000 08:05 312384
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/List/Util/Util.so
00139000-00141000 r-xp 00000000 08:08 98480      /lib/libnss_nis-2.4.so
00141000-00142000 r-xp 00007000 08:08 98480      /lib/libnss_nis-2.4.so
00142000-00143000 rwxp 00008000 08:08 98480      /lib/libnss_nis-2.4.so
00143000-0014c000 r-xp 00000000 08:08 98475      /lib/libnss_files-2.4.so
0014c000-0014d000 r-xp 00008000 08:08 98475      /lib/libnss_files-2.4.so
0014d000-0014e000 rwxp 00009000 08:08 98475      /lib/libnss_files-2.4.so
0019c000-0019f000 r-xp 00000000 08:05 312333
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/Fcntl/Fcntl.so
0019f000-001a0000 rwxp 00002000 08:05 312333
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/Fcntl/Fcntl.so
001a0000-002bf000 r-xp 00000000 08:08 98441      /lib/libcrypto.so.0.9.8a
002bf000-002d2000 rwxp 0011e000 08:08 98441      /lib/libcrypto.so.0.9.8a
002d2000-002d5000 rwxp 002d2000 00:00 0
004c7000-004cb000 r-xp 00000000 08:05 311983
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/Digest/MD5/MD5.so
004cb000-004cc000 rwxp 00003000 08:05 311983
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/Digest/MD5/MD5.so
0057e000-00582000 r-xp 00000000 08:05 312378
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IO/IO.so
00582000-00583000 rwxp 00003000 08:05 312378
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IO/IO.so
00697000-006bb000 r-xp 00000000 08:05 347389
/usr/lib/libk5crypto.so.3.0
006bb000-006bc000 rwxp 00024000 08:05 347389
/usr/lib/libk5crypto.so.3.0
006be000-006d6000 r-xp 00000000 08:05 347444
/usr/lib/libgssapi_krb5.so.2.2
006d6000-006d7000 rwxp 00017000 08:05 347444
/usr/lib/libgssapi_krb5.so.2.2
006e4000-006e6000 r-xp 00000000 08:08 98846      /lib/libutil-2.4.so
006e6000-006e7000 r-xp 00001000 08:08 98846      /lib/libutil-2.4.so
006e7000-006e8000 rwxp 00002000 08:08 98846      /lib/libutil-2.4.so
006eb000-006ec000 r-xp 006eb000 00:00 0          [vdso]
006ec000-00705000 r-xp 00000000 08:08 98377      /lib/ld-2.4.so
00705000-00706000 r-xp 00018000 08:08 98377      /lib/ld-2.4.so
00706000-00707000 rwxp 00019000 08:08 98377      /lib/ld-2.4.so
00709000-00836000 r-xp 00000000 08:08 98431      /lib/libc-2.4.so
00836000-00838000 r-xp 0012d000 08:08 98431      /lib/libc-2.4.so
00838000-00839000 rwxp 0012f000 08:08 98431      /lib/libc-2.4.so
00839000-0083c000 rwxp 00839000 00:00 0
0083e000-00861000 r-xp 00000000 08:08 98735      /lib/libm-2.4.so
00861000-00862000 r-xp 00022000 08:08 98735      /lib/libm-2.4.so
00862000-00863000 rwxp 00023000 08:08 98735      /lib/libm-2.4.so
00865000-00867000 r-xp 00000000 08:08 98506      /lib/libdl-2.4.so
00867000-00868000 r-xp 00001000 08:08 98506      /lib/libdl-2.4.so
00868000-00869000 rwxp 00002000 08:08 98506      /lib/libdl-2.4.so
0086b000-0087d000 r-xp 00000000 08:05 344354     /usr/lib/libz.so.1.2.3
0087d000-0087e000 rwxp 00011000 08:05 344354     /usr/lib/libz.so.1.2.3
0088b000-008ae000 r-xp 00000000 08:05 510959
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so
008ae000-008af000 rwxp 00022000 08:05 510959
/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/DBD/Pg/Pg.so
008b3000-008d3000 r-xp 00000000 08:05 344456     /usr/lib/libpq.so.4.1
008d3000-008d4000 rwxp 00020000 08:05 344456     /usr/lib/libpq.so.4.1
00a9c000-00aac000 r-xp 00000000 08:08 98737      /lib/libpthread-2.4.so
00aac000-00aad000 r-xp 0000f000 08:08 98737      /lib/libpthread-2.4.so
00aad000-00aae000 rwxp 00010000 08:08 98737      /lib/libpthread-2.4.so
00aae000-00ab0000 rwxp 00aae000 00:00 0
00ba1000-00bb3000 r-xp 00000000 08:08 98357      /lib/libnsl-2.4.so
00bb3000-00bb4000 r-xp 00011000 08:08 98357      /lib/libnsl-2.4.so
00bb4000-00bb5000 rwxp 00012000 08:08 98357      /lib/libnsl-2.4.so
00bb5000-00bb7000 rwxp 00bb5000 00:00 0
00be7000-00bf2000 r-xp 00000000 08:08 98736
/lib/libgcc_s-4.1.1-20060525.so.1
00bf2000-00bf3000 rwxp 0000a000 08:08 98736
/lib/libgcc_s-4.1.1-20060525.so.1
00c0f000-00c13000 r-xp 00000000 08:08 98466      /lib/libnss_dns-2.4.so
00c13000-00c14000 r-xp 00003000 08:08 98466      /lib/libnss_dns-2.4.so
00c14000-00c15000 rwxp 00004000 08:08 98466      /lib/libnss_dns-2.4.so
00d80000-00d85000 r-xp 00000000 08:08 98835      /lib/libcrypt-2.4.so
00d85000-00d86000 r-xp 00004000 08:08 98835      /lib/libcrypt-2.4.so
00d86000-00d87000 rwxp 00005000 08:08 98835      /lib/libcrypt-2.4.so
00d87000-00dae000 rwxp 00d87000 00:00 0
00dcd000-00dcf000 r-xp 00000000 08:08 98753      /lib/libcom_err.so.2.1
00dcf000-00dd0000 rwxp 00001000 08:08 98753      /lib/libcom_err.so.2.1
00dd2000-00de1000 r-xp 00000000 08:08 98500      /lib/libresolv-2.4.so
00de1000-00de2000 r-xp 0000e000 08:08 98500      /lib/libresolv-2.4.so
00de2000-00de3000 rwxp 0000f000 08:08 98500      /lib/libresolv-2.4.so
00de3000-00de5000 rwxp 00de3000 00:00 0
00de7000-00dea000 r-xp 00000000 08:05 344494
/usr/lib/libkrb5support.so.0.0
00dea000-00deb000 rwxp 00002000 08:05 344494
/usr/lib/libkrb5support.so.0.0
03a7a000-03aed000 r-xp 00000000 08:05 347438     /usr/lib/libkrb5.so.3.2
03aed000-03aef000 rwxp 00073000 08:05 347438     /usr/lib/libkrb5.so.3.2
03b83000-03cae000 r-xp 00000000 08:05 296285
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so
03cae000-03cb3000 rwxp 0012a000 08:05 296285
/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE/libperl.so
03cb3000-03cb5000 rwxp 03cb3000 00:00 0
05806000-05847000 r-xp 00000000 08:08 98467      /lib/libssl.so.0.9.8a
05847000-0584b000 rwxp 00040000 08:08 98467      /lib/libssl.so.0.9.8a
08048000-0804b000 r-xp 00000000 08:05 131923     /usr/bin/perl
0804b000-0804c000 rw-p 00002000 08:05 131923     /usr/bin/perl
08ebf000-091f7000 rw-p 08ebf000 00:00 0          [heap]
b7c4f000-b7c70000 rw-p b7c4f000 00:00 0
b7c70000-b7c71000 r--p 00747000 08:05 248275
/usr/lib/locale/locale-archive
b7c71000-b7d7c000 r--p 00266000 08:05 248275
/usr/lib/locale/locale-archive
b7d7c000-b7f7c000 r--p 00000000 08:05 248275
/usr/lib/locale/locale-archive
b7f7c000-b7f7f000 rw-p b7f7c000 00:00 0
b7f8d000-b7f8e000 rw-p b7f8d000 00:00 0
bff0b000-bff20000 rw-p bff0b000 00:00 0          [stack]

Re: BUG #2766: erratic segfault in libpq/DBD::Pg

From
Tom Lane
Date:
"Karl DeBieechop" <kdebisschop@alert.infoplease.com> writes:
> error is completely erratic - will work 10 times, then fail. or fail 10 time
> then work. So I have not been able to find a reporduacble test case. But
> here's a trace:

> *** glibc detected *** /usr/bin/perl: realloc(): invalid pointer: 0x091c2f94
> ***

This looks like either an extra-free or a memory clobber problem.  Try
running your example under a debugging malloc package to see if that
doesn't narrow down the source of the problem.  I've had success with
ElectricFence in the past, valgrind might help too.

            regards, tom lane