This issue is similar to Bug 43857 - exiting prefork child doesn't clear request pool. The bug 43857 is related to prefork child, this is related to mpm-worker child. stack trace: Thread 1 (Thread 0x7fafad5e0740 (LWP 14219)): #0 0x00007fafac77b425 in raise () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #1 0x00007fafac77eb8b in abort () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #2 0x00007fafac7740ee in ?? () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #3 0x00007fafac774192 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6 No symbol table info available. #4 0x00007fafacf7ce3f in reslist_cleanup (data_=0x7fafae9e8bd0) at misc/apr_reslist.c:161 rv = 0 rl = 0x7fafae9e8bd0 res = 0x7fffb9044920 __PRETTY_FUNCTION__ = "reslist_cleanup" #5 0x00007fafacd40c30 in run_cleanups (cref=0x7fafae9e8b78) at memory/unix/apr_pools.c:2352 c = 0x7fafae9e8d10 #6 0x00007fafacd3fabf in apr_pool_destroy (pool=0x7fafae9e8b58) at memory/unix/apr_pools.c:814 active = 0x7fafaeaed640 allocator = 0x7fafae8be010 #7 0x00007fafacd3faa2 in apr_pool_destroy (pool=0x7fafae95a268) at memory/unix/apr_pools.c:811 active = 0x7fafae95a268 allocator = 0x7fafaeb8aa08 #8 0x00007fafad67895e in clean_child_exit (code=0) at worker.c:430 No locals. #9 0x00007fafad67ad59 in child_main (child_num_arg=11) at worker.c:1367 threads = 0x7fafaecd9cf0 rv = 1 ts = 0x7fafae95be10 thread_attr = 0x7fafae95be30 start_thread_id = 0x7fafae95be90 #10 0x00007fafad67ae58 in make_child (s=0x7fafae8ed4c0, slot=11) at worker.c:1418 pid = 0 #11 0x00007fafad67b59f in perform_idle_server_maintenance () at worker.c:1626 i = 0 j = 25 idle_thread_count = 73 ws = 0x7fafad485f60 ps = 0x7fafad44e1e0 free_length = 1 totally_free_length = 1 free_slots = {11, 2, 3, 4, 5, 6, 1, 2, 3, 4, -1388432843, 32687, 134, 0, 6, 0, 5952, 0, -1386065568, 32687, -1190900960, 32767, -1395325068, 32687, 1395745853, 0, -1400690833, 32687, 0, 0, -1395323367, 32687} last_non_dead = 14 total_non_dead = 15 active_thread_count = 155 #12 0x00007fafad67b916 in server_main_loop (remaining_children_to_start=0) at worker.c:1752 old_gen = -1365807208 child_slot = 0 exitwhy = 6 status = 6 processed_status = 0 pid = {pid = -1, in = 0x7fafae976f98, out = 0x0, err = 0xffffffffffffffff} i = 25 #13 0x00007fafad67bd69 in worker_run (_pconf=0x7fafae8c4138, plog=0x7fafae8f1378, s=0x7fafae8ed4c0) at worker.c:1823 remaining_children_to_start = 0 rv = 0 #14 0x00007fafad62eebb in ap_run_mpm (pconf=0x7fafae8c4138, plog=0x7fafae8f1378, s=0x7fafae8ed4c0) at mpm_common.c:98 pHook = 0x7fafae963600 n = 0 rv = -1 #15 0x00007fafad62717c in main (argc=11, argv=0x7fffb9044f28) at main.c:777 c = 68 'D' showcompile = 0 showdirectives = 0 confname = 0x7fafad67fe73 "conf/httpd.conf" def_server_root = 0x7fafad67fe83 "/opt/bg/deploy/apache24" temp_error_log = 0x0 error = 0x0 process = 0x7fafae8c2218 pconf = 0x7fafae8c4138 plog = 0x7fafae8f1378 ptemp = 0x7fafae8ef348 pcommands = 0x7fafae8e6248 opt = 0x7fafae8e6338 rv = 0 mod = 0x7fafad89d800 opt_arg = 0x7fffb9046c54 "env_prod" signal_server = 0x7fafad6625aa At apr_reslist.c:161 #4 0x00007fafacf7ce3f in reslist_cleanup (data_=0x7fafae9e8bd0) at misc/apr_reslist.c:161= assert(rl->ntotal == 0); (gdb) print rl->ntotal $1 = 9 (gdb) print rl->nidle $2 = 0