PHP 4.0RC1, RC2, and 4.0.0 compiled with --with-oci8 --enable-track-vars, Apache 1.3.12

After 15 or 20 Oracle runtime errors are encountered, sessions stop working (I do not know for sure this is the trigger but it's the closest correlation I can find). Any attempts to call any session function (session_start, session_register, etc.) result in a hang. Starting and stopping httpd does not help (for that matter, neither does deleting and rebuilding them from scratch). The only solution is to restart the entire machine. No other performance problems are observed; Oracle queries, etc., still work fine as long as no PHP sessions are used.

Here's a gdb backtrace from PHP hung in session_start():

Program received signal SIGINT, Interrupt.
0x40689001 in __flock () from /lib/libc.so.6
(gdb) bt
#0  0x40689001 in __flock () from /lib/libc.so.6
#1  0x80a70a8 in _ps_files_open (data=0x82146bc, 
    key=0x81d81a4 "c96d9f7b6b461a9ee9378222de33551f") at mod_files.c:141
#2  0x80a72b1 in _ps_read_files (mod_data=0x818a770, 
    key=0x81d81a4 "c96d9f7b6b461a9ee9378222de33551f", val=0xbfffe310, 
    vallen=0xbfffe314) at mod_files.c:232
#3  0x80a4e2e in _php_session_initialize () at session.c:436
#4  0x80a59a4 in _php_session_start () at session.c:819
#5  0x80a6a1c in php_if_session_start (ht=0, return_value=0x821412c, 
    this_ptr=0x0, return_value_used=0) at session.c:1177
#6  0x80de00c in execute (op_array=0x82280d0) at ./zend_execute.c:1574
#7  0x80de1db in execute (op_array=0x820335c) at ./zend_execute.c:1614
#8  0x807b8fb in php_execute_script (primary_file=0xbffffa80) at main.c:1200
#9  0x80964d0 in apache_php_module_main (r=0x81e82ec, fd=19, 
    display_source_mode=0) at sapi_apache.c:93
#10 0x8077f2c in send_php (r=0x81e82ec, display_source_mode=0, 
    filename=0x81e8dbc "/www/live/firmlist.php") at mod_php4.c:512
#11 0x8077f5f in send_parsed_php (r=0x81e82ec) at mod_php4.c:524
#12 0x80f9e83 in ap_invoke_handler ()
#13 0x810d3b9 in process_request_internal ()
#14 0x810d41c in ap_process_request ()
#15 0x8104cbe in child_main ()
#16 0x8104e4c in make_child ()
#17 0x8104fa9 in startup_children ()
#18 0x81055d6 in standalone_main ()
#19 0x8105d63 in main ()
#20 0x405fc1eb in __libc_start_main (main=0x8105a1c <main>, argc=2, 
    argv=0xbffffc44, init=0x805ef70 <_init>, fini=0x81332dc <_fini>, 
    rtld_fini=0x4000a610 <_dl_fini>, stack_end=0xbffffc3c)
    at ../sysdeps/generic/libc-start.c:90