Como faço para diagnosticar essa falha de segmentação do PHP?

Estou executando um trabalho PHP de linha de comando que está resultando em uma falha de segmentação. Este trabalho tem funcionado por um longo tempo, mas processa algo que é enviado por e-mail. Aparentemente, há algo neste e-mail que o quebra, mas não tenho ideia do que. Se eu colocar o arquivo principal no gdb, realmente não será ajuda:

$ gdb /usr/local/bin/php core.20381 
GNU gdb (GDB) 7.1-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/local/bin/php...done.
[New Thread 20381]

warning: Can't read pathname for load map: Input/output error.
Reading symbols from /lib/libcrypt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libcrypt.so.1
Reading symbols from /lib/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/librt.so.1
Reading symbols from /usr/lib/libmysqlclient_r.so.15...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libmysqlclient_r.so.15
Reading symbols from /lib/libpthread.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/libpthread.so.0
Reading symbols from /lib/libz.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libz.so.1
Reading symbols from /usr/lib/libmcrypt.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libmcrypt.so.4
Reading symbols from /usr/lib/libltdl.so.7...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libltdl.so.7
Reading symbols from /lib/libpng12.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/libpng12.so.0
Reading symbols from /lib/libm.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libdl.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/libdl.so.2
Reading symbols from /lib/libnsl.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libnsl.so.1
Reading symbols from /usr/lib/libcurl-gnutls.so.4...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libcurl-gnutls.so.4
Reading symbols from /usr/lib/libxml2.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libxml2.so.2
Reading symbols from /lib/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/libresolv.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/libresolv.so.2
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /usr/lib/libidn.so.11...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libidn.so.11
Reading symbols from /usr/lib/liblber-2.4.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/liblber-2.4.so.2
Reading symbols from /usr/lib/libldap_r-2.4.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libldap_r-2.4.so.2
Reading symbols from /usr/lib/libgssapi_krb5.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libgssapi_krb5.so.2
Reading symbols from /usr/lib/libgnutls.so.26...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libgnutls.so.26
Reading symbols from /lib/libgcrypt.so.11...(no debugging symbols found)...done.
Loaded symbols for /lib/libgcrypt.so.11
Reading symbols from /usr/lib/libsasl2.so.2...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libsasl2.so.2
Reading symbols from /usr/lib/libkrb5.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libkrb5.so.3
Reading symbols from /usr/lib/libk5crypto.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libk5crypto.so.3
Reading symbols from /lib/libcom_err.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/libcom_err.so.2
Reading symbols from /usr/lib/libkrb5support.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libkrb5support.so.0
Reading symbols from /lib/libkeyutils.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libkeyutils.so.1
Reading symbols from /usr/lib/libtasn1.so.3...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/libtasn1.so.3
Reading symbols from /lib/libgpg-error.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/libgpg-error.so.0
Reading symbols from /lib/libgcc_s.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/libnss_files.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/libnss_files.so.2
Can't read symbols from system-supplied DSO at 0x7fffb4bfc000: File truncated
Core was generated by `/usr/local/bin/php /src/prod/current/utils/cron.php --run=/utils/proces'.
Program terminated with signal 11, Segmentation fault.
#0  match (
    eptr=0x1370a887 "/td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t\t\t"..., ecode=0x133dc3aa "N", 
    mstart=0x13708600 "<html>\n<head>\n<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1, maximum-scale=1\">\n\n</head>\n\n<body style=\"padding"..., markptr=0x0, offset_top=4, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=17680) at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:470
470 {

Se eu fizer um 'bt', eu apenas recebo esta declaração "match" repetidas vezes. Aqui estão os primeiros:

#1  0x000000000046ef1e in match (
    eptr=0x1370a887 "/td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t\t\t"..., ecode=0x133dc3a5 "_", mstart=<value optimized out>, markptr=<value optimized out>, 
    offset_top=<value optimized out>, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=17679) at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:803
#2  0x0000000000479789 in match (
    eptr=0x1370a887 "/td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t\t\t"..., ecode=0x133dc5ca "V\002%\033U\002.", mstart=<value optimized out>, 
    markptr=<value optimized out>, offset_top=<value optimized out>, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=<value optimized out>)
    at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:1623
#3  0x000000000046ef1e in match (
    eptr=0x1370a886 "</td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t\t"..., ecode=0x133dc3a5 "_", mstart=<value optimized out>, markptr=<value optimized out>, 
    offset_top=<value optimized out>, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=17677) at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:803
#4  0x0000000000479789 in match (
    eptr=0x1370a886 "</td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t\t"..., ecode=0x133dc5ca "V\002%\033U\002.", mstart=<value optimized out>, 
    markptr=<value optimized out>, offset_top=<value optimized out>, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=<value optimized out>)
    at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:1623
#5  0x000000000046ef1e in match (
    eptr=0x1370a885 "\t</td>\n\t\t\t\t\t\t\n\t\t\t\t\t</tr>\n\t\t\t\t\t\n\t\t\t\t</table>\n\t\t\t</td>\n\t\t</tr>\n\t\t\n\t\t<tr>\n\t\t\t<td style=\"border-top:3px solid #efefef; padding:20px 10px;\">\n\t\t\t\t<table style=\"width:100%;\">\n\t\t\t\t\t<tr>\n\t\t\t\t\t\t\n", '\t' <repeats 12 times>, "\n\t\t"..., ecode=0x133dc3a5 "_", mstart=<value optimized out>, markptr=<value optimized out>, 
    offset_top=<value optimized out>, md=0x7fffb4b1b620, ims=0, eptrb=0x0, flags=0, rdepth=17675) at /home/farmer/srcs/php-5.3.4/ext/pcre/pcrelib/pcre_exec.c:803

Eu estou realmente em uma perda aqui. Eu tentei executar o comando no strace e parece ser seg-faulting na biblioteca PEAR Mail_Queue. Aqui está o fim do strace (algumas informações de identificação foram removidas):

lstat("/src/prod/releases/20121025202143/www/application/pear/MDB2/Driver/mysql.php", {st_mode=S_IFREG|0770, st_size=55723, ...}) = 0
lstat("/src/prod/releases/20121025202143/www/application/pear/MDB2/Driver", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
lstat("/src/prod/releases/20121025202143/www/application/pear/MDB2", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
lstat("/src/prod/releases/20121025202143/www/application/pear", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
open("/src/prod/releases/20121025202143/www/application/pear/MDB2/Driver/mysql.php", O_RDONLY) = 6
fstat(6, {st_mode=S_IFREG|0770, st_size=55723, ...}) = 0
fstat(6, {st_mode=S_IFREG|0770, st_size=55723, ...}) = 0
fstat(6, {st_mode=S_IFREG|0770, st_size=55723, ...}) = 0
mmap(NULL, 55723, PROT_READ, MAP_SHARED, 6, 0) = 0x2b49f7bb4000
brk(0x987b000)                          = 0x987b000
brk(0x98bb000)                          = 0x98bb000
munmap(0x2b49f7bb4000, 55723)           = 0
close(6)                                = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 6
fcntl(6, F_SETFL, O_RDONLY)             = 0
fcntl(6, F_GETFL)                       = 0x2 (flags O_RDWR)
fcntl(6, F_GETFL)                       = 0x2 (flags O_RDWR)
fcntl(6, F_SETFL, O_RDWR|O_NONBLOCK)    = 0
connect(6, {sa_family=AF_INET, sin_port=htons(3306), sin_addr=inet_addr("IP ADDRESS TO DB SERVER REMOVED")}, 16) = -1 EINPROGRESS (Operation now in progress)
fcntl(6, F_SETFL, O_RDWR)               = 0
poll([{fd=6, events=POLLIN|POLLPRI}], 1, 60000) = 1 ([{fd=6, revents=POLLIN}])
setsockopt(6, SOL_SOCKET, SO_RCVTIMEO, "\2003\341\1\0\0\0\0\0\0\0\0\0\0\0\0", 16) = 0
setsockopt(6, SOL_SOCKET, SO_SNDTIMEO, "\2003\341\1\0\0\0\0\0\0\0\0\0\0\0\0", 16) = 0
setsockopt(6, SOL_IP, IP_TOS, [8], 4)   = 0
setsockopt(6, SOL_TCP, TCP_NODELAY, [1], 4) = 0
setsockopt(6, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
poll([{fd=6, events=POLLIN}], 1, 60000) = 1 ([{fd=6, revents=POLLIN}])
read(6, "C\0\0\0\n5.1.37-1ubuntu5.5-log\0Q\257\3\0009"..., 16384) = 71
write(6, "=\0\0\1\205\242\2\0\0\0\0@\10\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 65) = 65
read(6, "\7\0\0\2\0\0\0\2\0\0\0", 16384) = 11
poll([{fd=6, events=POLLIN|POLLPRI}], 1, 0) = 0 (Timeout)
write(6, "\10\0\0\0\2xxxxx", 12)      = 12
read(6, "\7\0\0\1\0\0\0\2\0\0\0", 16384) = 11
lstat("/src/prod/current/www/application/pear/Mail/mime.php", {st_mode=S_IFREG|0770, st_size=50252, ...}) = 0
lstat("/src/prod/current/www/application/pear/Mail", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
lstat("/src/prod/current/www/application/pear", {st_mode=S_IFDIR|0770, st_size=4096, ...}) = 0
lstat("/src/prod/current/www/application", {st_mode=S_IFDIR|0776, st_size=4096, ...}) = 0
--- SIGSEGV (Segmentation fault) @ 0 (0) ---
+++ killed by SIGSEGV +++
Segmentation fault

Se alguém tem alguma idéia ou ponteiros para linhas de investigação, eu realmente aprecio isso. Estou realmente perplexo com isso.

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