Hi All,
I'd appreciate some feedback on an issue I'm experiencing. I've spent quite
some time researching the problem as it causes a serious outage in our
application. I've searched the Web, Stack Overflow, this list's mail
archives, the latest Apache bugs, and more, but have not been able to find
any reports of a similar issue.
Background. I'm running the latest Apache 2.4.51 on Amazon Linux with
mod_proxy, mod_php and mod_ssl with varnish in front. Some requests to our
application take about 45 seconds to complete so there is a warm-up cache
procedure at regular intervals during the day which primes the varnish
cache. The following steps reliably cause Apache to hang, requiring a
manual restart:
1. Varnish cache is cleared, causing spike in load on httpd
2. Warm-up cache process kicks off with 2 long running requests (45
seconds each). This is a PHP application running under mod_php - each
process grows up to 700 MB, so the application kills the httpd child
process at the end to release the memory, using posix_kill(PID, 28).
3. Apache hangs and does not recover. Varnish serves 503s.
4. Manual restart required: service httpd restart
5. Errors in the log show that 2 children had segmentation faults,
presumably the 2 with long running processes.
Albeit ugly, this process has been running for a year and a half without
any issues. We traced the date that crashes started to the date Apache was
upgraded from version 2.4.46 to 2.4.48 and as you can see it's still an
issue in 2.4.51.
See the error_log below and details about the installation.
Any feedback on where to report this issue would be much appreciated.
Thanks.
Patrick
--
# cat /var/log/httpd/error_log
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
*** Error in `/usr/sbin/httpd': corrupted size vs. prev_size:
0x0000557f94567e4f ***
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
httpd: misc/apr_reslist.c:161: reslist_cleanup: Assertion `rl->ntotal == 0'
failed.
[Sun Oct 17 15:53:47.990497 2021] [core:notice] [pid 2620] AH00052: child
pid 3166 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990531 2021] [core:notice] [pid 2620] AH00052: child
pid 3483 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990545 2021] [core:notice] [pid 2620] AH00052: child
pid 2657 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990557 2021] [core:notice] [pid 2620] AH00052: child
pid 2660 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990568 2021] [core:notice] [pid 2620] AH00052: child
pid 2661 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990579 2021] [core:notice] [pid 2620] AH00052: child
pid 3172 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990592 2021] [core:notice] [pid 2620] AH00052: child
pid 2681 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990603 2021] [core:notice] [pid 2620] AH00052: child
pid 3254 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990615 2021] [core:notice] [pid 2620] AH00052: child
pid 2685 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990627 2021] [core:notice] [pid 2620] AH00052: child
pid 2688 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990639 2021] [core:notice] [pid 2620] AH00052: child
pid 3015 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990652 2021] [core:notice] [pid 2620] AH00052: child
pid 2696 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990664 2021] [core:notice] [pid 2620] AH00052: child
pid 2699 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990680 2021] [core:notice] [pid 2620] AH00052: child
pid 2710 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990692 2021] [core:notice] [pid 2620] AH00052: child
pid 2713 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990703 2021] [core:notice] [pid 2620] AH00052: child
pid 3250 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990716 2021] [core:notice] [pid 2620] AH00052: child
pid 2721 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990726 2021] [core:notice] [pid 2620] AH00052: child
pid 2724 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990739 2021] [core:notice] [pid 2620] AH00052: child
pid 2734 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990750 2021] [core:notice] [pid 2620] AH00052: child
pid 3471 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990769 2021] [core:notice] [pid 2620] AH00052: child
pid 3109 exit signal Aborted (6)
[Sun Oct 17 15:53:47.990781 2021] [core:notice] [pid 2620] AH00052: child
pid 2741 exit signal Segmentation fault (11)
*** Error in `/usr/sbin/httpd': corrupted size vs. prev_size:
0x0000557f94567e4f ***
[Sun Oct 17 15:53:48.056539 2021] [core:notice] [pid 2620] AH00052: child
pid 3019 exit signal Aborted (6)
[Sun Oct 17 15:53:48.056584 2021] [core:notice] [pid 2620] AH00052: child
pid 2707 exit signal Segmentation fault (11)
[Sun Oct 17 15:53:48.056599 2021] [core:notice] [pid 2620] AH00052: child
pid 2727 exit signal Aborted (6)
[Sun Oct 17 15:53:48.056667 2021] [mpm_prefork:notice] [pid 2620] AH00169:
caught SIGTERM, shutting down
[Sun Oct 17 15:53:48.151770 2021] [suexec:notice] [pid 3575] AH01232:
suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sun Oct 17 15:53:48.180621 2021] [http2:warn] [pid 3581] AH10034: The mpm
module (prefork.c) is not supported by mod_http2. The mpm determines how
things are processed in your server. HTTP/2 has more demands in this regard
and the currently selected mpm will just not do. This is an advisory
warning. Your server will continue to work, but the HTTP/2 protocol will be
inactive.
[Sun Oct 17 15:53:48.181146 2021] [lbmethod_heartbeat:notice] [pid 3581]
AH02282: No slotmem from mod_heartmonitor
[Sun Oct 17 15:53:48.243891 2021] [mpm_prefork:notice] [pid 3581] AH00163:
Apache/2.4.51 (Amazon) OpenSSL/1.0.2k-fips configured -- resuming normal
operations
[Sun Oct 17 15:53:48.243923 2021] [core:notice] [pid 3581] AH00094: Command
line: '/usr/sbin/httpd'
[Sun Oct 17 15:53:49.244527 2021] [mpm_prefork:error] [pid 3581] AH00161:
server reached MaxRequestWorkers setting, consider raising the
MaxRequestWorkers setting
# httpd -V
Server version: Apache/2.4.51 (Amazon)
Server built: Oct 8 2021 19:30:47
Server's Module Magic Number: 20120211:118
Server loaded: APR 1.6.3, APR-UTIL 1.5.4
Compiled using: APR 1.6.3, APR-UTIL 1.5.4
Architecture: 64-bit
Server MPM: prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="/var/run/httpd/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"
# httpd -M
Loaded Modules:
core_module (static)
so_module (static)
http_module (static)
access_compat_module (shared)
actions_module (shared)
alias_module (shared)
allowmethods_module (shared)
auth_basic_module (shared)
auth_digest_module (shared)
authn_anon_module (shared)
authn_core_module (shared)
authn_dbd_module (shared)
authn_dbm_module (shared)
authn_file_module (shared)
authn_socache_module (shared)
authz_core_module (shared)
authz_dbd_module (shared)
authz_dbm_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_owner_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cache_module (shared)
cache_disk_module (shared)
cache_socache_module (shared)
data_module (shared)
dbd_module (shared)
deflate_module (shared)
dir_module (shared)
dumpio_module (shared)
echo_module (shared)
env_module (shared)
expires_module (shared)
ext_filter_module (shared)
filter_module (shared)
headers_module (shared)
http2_module (shared)
include_module (shared)
info_module (shared)
log_config_module (shared)
logio_module (shared)
macro_module (shared)
mime_magic_module (shared)
mime_module (shared)
negotiation_module (shared)
remoteip_module (shared)
reqtimeout_module (shared)
request_module (shared)
rewrite_module (shared)
setenvif_module (shared)
slotmem_plain_module (shared)
slotmem_shm_module (shared)
socache_dbm_module (shared)
socache_memcache_module (shared)
socache_shmcb_module (shared)
status_module (shared)
substitute_module (shared)
suexec_module (shared)
unixd_module (shared)
userdir_module (shared)
version_module (shared)
vhost_alias_module (shared)
watchdog_module (shared)
dav_module (shared)
dav_fs_module (shared)
dav_lock_module (shared)
lua_module (shared)
mpm_prefork_module (shared)
proxy_module (shared)
lbmethod_bybusyness_module (shared)
lbmethod_byrequests_module (shared)
lbmethod_bytraffic_module (shared)
lbmethod_heartbeat_module (shared)
proxy_ajp_module (shared)
proxy_balancer_module (shared)
proxy_connect_module (shared)
proxy_express_module (shared)
proxy_fcgi_module (shared)
proxy_fdpass_module (shared)
proxy_ftp_module (shared)
proxy_http_module (shared)
proxy_hcheck_module (shared)
proxy_scgi_module (shared)
proxy_uwsgi_module (shared)
proxy_wstunnel_module (shared)
ssl_module (shared)
cgi_module (shared)
php7_module (shared)
# yum list | grep mod_
lighttpd-mod_authn_gssapi.x86_64 1.4.53-1.36.amzn1
amzn-updates
lighttpd-mod_authn_mysql.x86_64 1.4.53-1.36.amzn1
amzn-updates
lighttpd-mod_authn_pam.x86_64 1.4.53-1.36.amzn1
amzn-updates
lighttpd-mod_geoip.x86_64 1.4.53-1.36.amzn1
amzn-updates
lighttpd-mod_mysql_vhost.x86_64 1.4.53-1.36.amzn1
amzn-updates
mod_auth_kerb.x86_64 5.4-10.9.amzn1 amzn-main
mod_auth_mellon.x86_64 0.13.1-1.6.amzn1
amzn-updates
mod_auth_mysql.x86_64 1:3.0.0-18.10.amzn1 amzn-main
mod_auth_pgsql.x86_64 2.0.3-10.1.5.amzn1 amzn-main
mod_authz_ldap.x86_64 0.26-16.8.amzn1 amzn-main
mod_dav_svn.x86_64 1.9.7-1.54.amzn1 amzn-main
mod_fcgid.x86_64 2.3.9-1.6.amzn1 amzn-main
mod_geoip.x86_64 1.2.7-1.2.amzn1 amzn-main
mod_nss.x86_64 1.0.10-1.13.amzn1 amzn-main
mod_perl.x86_64 2.0.7-7.28.amzn1
amzn-updates
mod_perl-devel.x86_64 2.0.7-7.28.amzn1
amzn-updates
mod_proxy_html.x86_64 3.1.2-7.3.amzn1 amzn-main
mod_python26.x86_64 3.3.1-17.20.amzn1 amzn-main
mod_python27.x86_64 3.3.1-17.20.amzn1 amzn-main
mod_security.x86_64 2.8.0-5.27.amzn1 amzn-main
mod_security_crs.noarch 2.2.8-2.5.amzn1 amzn-main
mod_security_crs-extras.noarch 2.2.8-2.5.amzn1 amzn-main
mod_ssl.x86_64 1:2.2.34-1.16.amzn1 amzn-main
mod_wsgi-python26.x86_64 3.2-6.12.amzn1
amzn-updates
mod_wsgi-python27.x86_64 3.2-6.12.amzn1
amzn-updates
*--*
*Patrick Verdon | Founder*
Web: www.youreko.com
Mobile: +44 (0)7809 296438
Skype: patrick_verdon
This entire communication is sent on behalf of
Youreko Ltd and is strictly confidential to and
for the sole use of the intended addressee.
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