Hi !
I have php-4.0.1pl2 compiled with following options:
--with-interbase --with-apache --enable-track-vars
A lot of messages like: "[notice] child pid XXXX exit signal Segmentation fault (11)" apper in my error-log file.
I've backtrace in gdb (by the way, httpd won't produce core) as following:

#0  0x401e5dd3 in __writev (fd=5, vector=0xbfffdbe4, count=2)
    at ../sysdeps/unix/sysv/linux/writev.c:50
#1  0x810568b in writev_it_all ()
#2  0x8105ac0 in large_write ()
#3  0x8105b84 in ap_bwrite ()
#4  0x81173ce in ap_rwrite ()
#5  0x8079c36 in sapi_apache_ub_write ()
#6  0x80c681d in php_ub_body_write_no_header (
    str=0x82d40fc "</b></TD>\r\n\t<td align=\"right\" valign=\"middle\" bgcolor=
\"#003366\"></td>\r\n\t<TD ALIGN=\"left\" VALIGN=\"BASELINE\" bgcolor=\"#000000\
" class=\"activesrchtab\"> \r\n\t  <table border=\"0\" cellspacing=\"0\" cellpad
ding=\""..., str_length=305) at output.c:270
#7  0x80c664c in php_body_write (
    str=0x82d40fc "</b></TD>\r\n\t<td align=\"right\" valign=\"middle\" bgcolor=
\"#003366\"></td>\r\n\t<TD ALIGN=\"left\" VALIGN=\"BASELINE\" bgcolor=\"#000000\
" class=\"activesrchtab\"> \r\n\t  <table border=\"0\" cellspacing=\"0\" cellpad
ding=\""..., str_length=305) at output.c:84
#8  0x807bd22 in php_body_write_wrapper (
    str=0x82d40fc "</b></TD>\r\n\t<td align=\"right\" valign=\"middle\" bgcolor=
\"#003366\"></td>\r\n\t<TD ALIGN=\"left\" VALIGN=\"BASELINE\" bgcolor=\"#000000\
" class=\"activesrchtab\"> \r\n\t  <table border=\"0\" cellspacing=\"0\" cellpad
ding=\""..., str_length=305) at main.c:688

another backtrace:

#0  0x401994a7 in memcpy (dstpp=0x0, srcpp=0x829e700, len=24)
    at ../sysdeps/generic/memcpy.c:55
#1  0x400529de in gds__msg_lookup () from /usr/lib/libgds.so
#2  0x40052643 in gds__msg_format () from /usr/lib/libgds.so
#3  0x400522f5 in gds__interprete () from /usr/lib/libgds.so
#4  0x4004cd2d in isc_interprete () from /usr/lib/libgds.so
#5  0x8089517 in _php_ibase_error () at interbase.c:245
#6  0x80896f2 in _php_ibase_free_result (ib_result=0x82b3c54)
    at interbase.c:356
#7  0x80dd4da in list_entry_destructor (ptr=0x82b73cc) at zend_list.c:253
#8  0x80dc47e in zend_hash_del_key_or_index (ht=0x819e3f0, arKey=0x0,
    nKeyLength=0, h=7, flag=1) at zend_hash.c:515
#9  0x80dd22f in zend_list_delete (id=7) at zend_list.c:59
#10 0x80d9007 in _zval_dtor (zvalue=0x82d8a3c) at zend_variables.c:80
#11 0x80d437a in _zval_ptr_dtor (zval_ptr=0x82ae8b0) at zend_execute_API.c:272
#12 0x80dc519 in zend_hash_destroy (ht=0x81ff344) at zend_hash.c:544
#13 0x80d8fe8 in _zval_dtor (zvalue=0x820875c) at zend_variables.c:75
#14 0x80d437a in _zval_ptr_dtor (zval_ptr=0x81ff390) at zend_execute_API.c:272
#15 0x80dc519 in zend_hash_destroy (ht=0x819e2d8) at zend_hash.c:544
#16 0x80d41e6 in shutdown_executor () at zend_execute_API.c:172
#17 0x80d998b in zend_deactivate () at zend.c:511
#18 0x807bcc4 in php_request_shutdown (dummy=0x0) at main.c:661
#19 0x807a046 in php_apache_request_shutdown ()
#20 0x8103ace in run_cleanups ()

Thank you beforehand,
stan.