I'm using Apache 2.0.43 and PHP 4.2.3 on HPUX 11.00. I also have OCI8 enabled.

PHP is compiled with: --with-oci8 --with-apxs2

Starting Apache/PHP works fine. Accessing PHP pages also works great. However, when stopping Apache using "apachectl stop" I get a core dump.

Here is the stack trace:
#0  0xc01f2740 in kill () from /usr/lib/libc.2
#1  0xad158 in sig_coredump (sig=-1) at prefork.c:367
#2  <signal handler called>
#3  0xc22b1cc0 in php_apache_sapi_send_headers (sapi_headers=0x400e18d8, tsrm_ls=0x400e1368) at sapi_apache2.c:126
#4  0xc22bdffc in sapi_send_headers (tsrm_ls=0x400e1368) at SAPI.c:600
#5  0xad158 in sig_coredump (sig=2078470596) at prefork.c:367
#6  0xc22c4bb0 in php_ub_body_write (str=0x7bff27d0 "OCIDebug: START php_mshutdown_oci<br />\n", str_length=40, tsrm_ls=0x400e1368)
    at output.c:479
#7  0xc22c396c in php_body_write (str=0x400e18d8 "", str_length=1074664296, tsrm_ls=0x400e1888) at output.c:101
#8  0xc22b4b24 in php_printf (format=0x7be590b4 "OCIDebug: %s<br />\n") at main.c:355
#9  0xc22ed738 in oci_debug (format=0x7be58d1c "START php_mshutdown_oci") at oci8.c:1046
#10 0xad158 in sig_coredump (sig=1074664296) at prefork.c:367
#11 0xc22a6ab4 in module_destructor (module=0x7be2f1c4) at zend_API.c:1127
#12 0xad158 in sig_coredump (sig=1074972864) at prefork.c:367
#13 0xc22a18b0 in zend_shutdown (tsrm_ls=0x7be2f1c4) at zend.c:492
#14 0xc22b75a0 in php_module_shutdown (tsrm_ls=0x400e1368) at main.c:1052
#15 0xad158 in sig_coredump (sig=2078470596) at prefork.c:367
#16 0xc22b2b08 in php_apache_server_shutdown (tmp=0x400e18d8) at sapi_apache2.c:430
#17 0xc13239a4 in run_cleanups (c=0x0) at apr_pools.c:1961
#18 0xc1322cc4 in apr_pool_clear (pool=0x4004b528) at apr_pools.c:709
#19 0xb7c04 in main (argc=4, argv=0x7bff1d3c) at main.c:600

A print of the ctx variable in sapi_apache2.c at line 126 shows a value of 0x0. This is why to core dump occurs.

Adding the following line just before line 126 fixes the problem:
if (!ctx) return SAPI_HEADER_SEND_FAILED;