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Aseem Mohanty
aseem at metaweb.com
Wed Jun 27 18:45:27 EDT 2007
Yes, hence the exotic phraseology. Results for the various combinations are below:
1. mod_python only, no mod_auth* modules: leaks
2. mod_auth_digest only, no other mod_auth*, no mod_python: does not leak
3. mod_authz_host only, no other mod_auth*, no mod_python: does not leak
4. mod_python + mod_authz_host, no mod_auth_digest: leaks
5. mod_python + mod_auth_digest, no mod_authz_host: leaks < (1) or (4)
6. mod_python + mod_auth_digest + mod_authz_host: does not leak
NOTE: 'does not leak' implies ~50-100K leakage per graceful restart
(5) leaks ~500-600K per graceful restart
zero load on server
As far as I can tell there is definitely some sinister interaction going on
between these three modules. Unfortunately not being conversant with apache
module development, I cannot really say what.
Thanks.
AM
Jim Gallacher wrote:
> Aseem Mohanty wrote:
>> This may sound quite exotic
>
>
> Why yes, it does? Interaction between these modules resulting in a
> memory leak sure sounds weird. Did you try it with *only* mod_python
> loaded? (ie, without mod_authz_host)
>
> Jim
>
>> but here it is:
>>
>> In a vanilla apache2.2.x configuration if I only load mod_authz_host
>> and none of
>> the other mod_auth* modules, every graceful restart causes ~1Mb leak
>> in the
>> parent process. This is with mod_python loaded. Without mod_python the
>> memory profile remains unchanged.
>>
>> Steps to reproduce:
>> Gentoo:
>> 1. In /etc/apache2/httpd.conf comment out all "LoadModule auth*"
>> directives except
>> LoadModule authz_host_module modules/mod_authz_host.so
>>
>> Ubuntu Feisty (repos):
>> 1. In /etc/apache2/mods-enabled rename auth*.load files except
>> authz_host.load
>> to auth*.load.not
>>
>> Ubuntu Feisty (httpd built from source):
>> 1. In conf/httpd.conf comment out all "LoadModule auth*" directives
>> except
>> LoadModule authz_host_module modules/mod_authz_host.so
>>
>> 2. Start apache
>> 3. Track apache parent process: top -d1 -p $(pgrep -o apache/httpd)
>> 4. Hit apache instances with graceful restarts:
>> for i in $(seq 150); do echo $i; kill -USR1 $(pgrep -o apache/httpd);
>> sleep 2; done
>>
>> In this case the parent will leak ~1Mb per restart. If however in each
>> of the
>> configurations mod_auth_digest.so is also loaded the leak is only
>> about 150-200K
>> or so per graceful restart. This is on a server with 0 load. In my
>> case it
>> caused apache instances that were restarted every 55 minutes to grow
>> up to 300Mb
>> in a week.
>>
>> Tested on:
>> 1. Ubuntu Feisty (built from source httpd-2.2.4, mod_python-3.3.1):
>> ./configure --prefix=/opt --enable-modules=all
>> --enable-mods-shared=all --enable-so --with-included-apr
>> Server version: Apache/2.2.4 (Unix)
>> Server built: Jun 27 2007 09:34:16
>> Server's Module Magic Number: 20051115:4
>> Server loaded: APR 1.2.8, APR-Util 1.2.8
>> Compiled using: APR 1.2.8, APR-Util 1.2.8
>> Architecture: 32-bit
>> Server MPM: Prefork
>> threaded: no
>> forked: yes (variable process count)
>> Server compiled with....
>> -D APACHE_MPM_DIR="server/mpm/prefork"
>> -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=128
>> -D HTTPD_ROOT="/opt/share/apache2"
>> -D SUEXEC_BIN="/opt/share/apache2/bin/suexec"
>> -D DEFAULT_PIDLOG="logs/httpd.pid"
>> -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
>> -D DEFAULT_LOCKFILE="logs/accept.lock"
>> -D DEFAULT_ERRORLOG="logs/error_log"
>> -D AP_TYPES_CONFIG_FILE="conf/mime.types"
>> -D SERVER_CONFIG_FILE="conf/httpd.conf"
>>
>>
>> 2. gentoo (64 bit dual proc AMD):
>> Linux host1 2.6.16-gentoo-r9 #7 SMP Fri Mar 16 17:35:26 UTC 2007
>> x86_64 AMD
>> Opteron(tm) Processor 248 AuthenticAMD GNU/Linux
>>
>> Server version: Apache/2.2.4 (Unix)
>> Server built: Jun 26 2007 19:29:33
>> Server's Module Magic Number: 20051115:4
>> Server loaded: APR 1.2.8, APR-Util 1.2.8
>> Compiled using: APR 1.2.8, APR-Util 1.2.8
>> Architecture: 64-bit
>> Server MPM: Prefork
>> threaded: no
>> forked: yes (variable process count)
>> Server compiled with....
>> -D APACHE_MPM_DIR="server/mpm/prefork"
>> -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=128
>> -D HTTPD_ROOT="/usr"
>> -D SUEXEC_BIN="/usr/sbin/suexec"
>> -D DEFAULT_PIDLOG="/var/run/httpd.pid"
>> -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
>> -D DEFAULT_LOCKFILE="/var/run/accept.lock"
>> -D DEFAULT_ERRORLOG="logs/error_log"
>> -D AP_TYPES_CONFIG_FILE="/etc/apache2/mime.types"
>> -D SERVER_CONFIG_FILE="/etc/apache2/httpd.conf"
>>
>> 3. Ubuntu Feisty (32 bit Intel core duo - ubuntu repos):
>> Linux host2 2.6.20-16-generic #2 SMP Thu Jun 7 20:19:32 UTC 2007 i686
>> GNU/Linux
>>
>> Server version: Apache/2.2.3
>> Server built: Jan 15 2007 18:14:50
>> Server's Module Magic Number: 20051115:3
>> Server loaded: APR 1.2.7, APR-Util 1.2.7
>> Compiled using: APR 1.2.7, APR-Util 1.2.7
>> Architecture: 32-bit
>> Server MPM: Prefork
>> threaded: no
>> forked: yes (variable process count)
>> Server compiled with....
>> -D APACHE_MPM_DIR="server/mpm/prefork"
>> -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=128
>> -D HTTPD_ROOT=""
>> -D SUEXEC_BIN="/usr/lib/apache2/suexec"
>> -D DEFAULT_PIDLOG="/var/run/apache2.pid"
>> -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
>> -D DEFAULT_LOCKFILE="/var/run/apache2/accept.lock"
>> -D DEFAULT_ERRORLOG="logs/error_log"
>> -D AP_TYPES_CONFIG_FILE="/etc/apache2/mime.types"
>> -D SERVER_CONFIG_FILE="/etc/apache2/apache2.conf"
>>
>> Bug or just an unexpected apache configuration?? I actually filed a
>> bug against apache core
>> (http://issues.apache.org/bugzilla/show_bug.cgi?id=42749) initially
>> not realizing that it could be a combination of factors that was
>> causing it and not just soe module not being loaded.
>>
>> Thanks.
>> AM
>> _______________________________________________
>> Mod_python mailing list
>> Mod_python at modpython.org
>> http://mailman.modpython.org/mailman/listinfo/mod_python
>>
>
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