Possible Bug Master/Slave repository with a 502 Bad Gateway. Not a HTTP/HTTPS translation problem

The following are the specifications of the error:

SERVER1 Master SVN Server compiled using subversion_1.5.6/apache_2.22.11/ruby_1.9.1p0/neon_0.28.3/apr_1.3.3/apr-iconv_1.2.1/apr-util_1.3.4/db_4.7.25/gsasl_0.2.29/jdk_1.6.012

configured and built through:

./configure --prefix=/opt/lampp --with-apr=/usr --with-apr-util=/usr --with-apxs=/opt/lampp/bin/apxs --with-zlib=/usr/lib --enable-experimental-libtool --with-jdk=/usr/src/jdk1.6.0_12 --with-ssl --with-sasl=/usr --with-berkeley-db=/usr/local/BerkeleyDB.4.7

compiler: GCC 4.1.2
arch: i686
Linux Kernel: 2.6.21.5 (SMP) * 2

Access through dav_svn through apache
Replication to slaves through svnsync post commit hooks

Operating System: Slackware 12.2
httpd.conf:
<Location /ivr>
    Order allow,deny
    Allow from all
    DAV svn
    SVNPath /raid/svn/repository/ivr
    AuthType Basic
    AuthName "IVR Repository"
    AuthUserFile /raid/svn/conf/svn-auth-file-eng
    Require valid-user
</Location>

including modules (of question)

LoadModule dav_module modules/mod_dav.so
LoadModule dav_fs_module modules/mod_dav_fs.so
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

SERVER2 Slave SVN Server compiled using subversion_1.5.6/apache_2.22.11/ruby_1.9.1p0/neon_0.28.3/apr_1.3.3/apr-iconv_1.2.1/apr-util_1.3.4/db_4.7.25/gsasl_0.2.29/jdk_1.6.012

configured and built through:

./configure --prefix=/opt/lampp --with-apr=/usr --with-apr-util=/usr --with-apxs=/opt/lampp/bin/apxs --with-zlib=/usr/lib --enable-experimental-libtool --with-jdk=/usr/src/jdk1.6.0_12 --with-ssl --with-sasl=/usr --with-berkeley-db=/usr/local/BerkeleyDB.4.7

compiler: GCC 4.1.2
arch: i686
Linux Kernel: 2.6.21.5 (SMP) * 4

Access through dav_svn through apache
Blocking of prerevprops changes to anything but svnsync account

Operating System: Slackware 12.0
httpd.conf:

<Location /ivr>
    Order allow,deny
    Allow from all
    DAV svn
    SVNPath /opt/svn/repository/ivr
    SVNMasterURI http://masterrepo/ivr
    AuthType Basic
    AuthName "IVR Repository"
    AuthUserFile /opt/svn/conf/svn-auth-file
    Require valid-user
  </Location>

including modules (of question)

LoadModule dav_module modules/mod_dav.so
LoadModule dav_fs_module modules/mod_dav_fs.so
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

/////////////////////////////////////

The repositories were set up at fsfs type.
I have been running a mirroring repository for quite some time holding approx 78GB combined data. There have never been any issues with any commits until recently.

It should be noted that no issue exists if a commit is made directly to the master server, only errors occur when a commit is made to a slave repository which forwards to the master server. I have found a keyword that causes the commit to comeback with a 502 Gateway error.

Scenario and it can be reproduced and test on your own to verify that this is the case:

Set up a master repository.
Replicate master repository to slave repository location.
using apache dav_svn style access: ie: svn co http://server/trunk
make sure slave server is set with the option SVNMasterURI to pass all commit traffic to the master server, and not to try to commit it localy completely destabalizing the slave server. (should have a prerevprops file in hooks the explicitly disallows this)

Now create a new working directory.
Import this into SVN
Checkout this working directory from the slave repository (assuming all your scripts are working properly )to start using your working directory.
now create a file in this working directory:
#touch randfile
add it to be committed
#svn add --force .
commit it
#svn ci -m "test"

It will commit properly
Everything works perfectly.
now here is where the failure comes.
edit the randfile

insert into the file the following:
/bin/kill
now save the file and try to commit it again:
#svn ci -m "test2"

FAILED: You will get a:

Transmitting file data .svn: Commit failed (details follow):
svn: Server sent unexpected return value (502 Bad Gateway) in response to PUT request for.....

Now modify the file by putting letters in front of and behind the /bin/kill
try committing again:
#svn ci -m "test3"

FAILED: You will still get a:

Transmitting file data .svn: Commit failed (details follow):
svn: Server sent unexpected return value (502 Bad Gateway) in response to PUT request for.....

now modify the file again one last time by altering the spelling of kill ie:
/bin/kil
now save the file and try commiting
#svn ci -m "test4"

Success. Notice it commit properly.
Now I was staring at the apache logfiles while this was happening the following was the result on the slaveserver:

[Wed Mar 18 22:02:59 2009] [error] [client xxx.xxx.xxx.xxx] (104)Connection reset by peer: proxy: error reading status line from remote server masterrepo

[Wed Mar 18 22:02:59 2009] [error] [client xxx.xxx.xxx.xxx] proxy: Error reading from remote server returned by /ivr/!svn/wrk/b2fd0c12-ff99-b94c-8718-107905d5d628/trunk/ga0/etc/logrotate.d/k.txt

xxx.xxx.xxx.xxx - svnuser [18/Mar/2009:22:02:59 -0400] "PUT /ivr/!svn/wrk/b2fd0c12-ff99-b94c-8718-107905d5d628/trunk/ga0/etc/logrotate.d/k.txt HTTP/1.1" 200 -

xxx.xxx.xxx.xxx - - [18/Mar/2009:22:02:59 -0400] "PUT /ivr/!svn/wrk/b2fd0c12-ff99-b94c-8718-107905d5d628/trunk/ga0/etc/logrotate.d/k.txt HTTP/1.1" 502 1406

xxx.xxx.xxx.xxx - svnuser [18/Mar/2009:22:02:59 -0400] "DELETE /ivr/!svn/act/b2fd0c12-ff99-b94c-8718-107905d5d628 HTTP/1.1" 204 -

/////////////////////////

Everything commits so far. Even having the file names as /bin/kill, but if there is any clearline text that has /bin/kill the commit will fail.

This has been reproduced on various other systems, but would like to know if anyone has seen or heard of this before, and can confirm my results, or denounce my results. As an additional note. svn commiting dirrectly to the master server even using the dav_svn does not exhibit these problems. Which leads me to believe it might be something with mod_proxy in apache.

Any help would be great.

~jonathan

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Received on 2009-03-19 04:37:24 CET