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Gavin LaRose - webserver dumping core

Gavin LaRose - webserver dumping core

by Arnold Pizer -
Number of replies: 0
inactiveTopicwebserver dumping core topic started 9/7/2005; 9:40:22 PM
last post 9/19/2005; 8:52:50 AM
userGavin LaRose - webserver dumping core  blueArrow
9/7/2005; 9:40:22 PM (reads: 710, responses: 5)
Hi all,

I just upgraded both our instructional technology servers to the HEAD version of WeBWorK, and one of them is now fairly regularly dumping core. I believe this is from one of the apache child processes dying. This is, unfortunately not easily diagnosed, because I don't know what the system is doing when it dumps the core.

Has anyone seen anything similar to this? Or have a suggestion for what might be going on or how to diagnose it?

Thanks, Gavin

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userGavin LaRose - Re: webserver dumping core  blueArrow
9/8/2005; 3:22:58 PM (reads: 795, responses: 0)
Follow-up: this may be due to an error on the permissions of a log directory, causing the webserver to be unable to log answers.

I hope everyone is finding their academic terms starting smoothly.

Gavin

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userMichael Gage - Re: webserver dumping core  blueArrow
9/10/2005; 12:44:13 PM (reads: 768, responses: 0)
Hi Gavin,

We ran into segmentation faults just recently. Sam found out that it was a conflict between mod_perl and mod_php.

There are hints at http://modperlbook.org/html/ch22_03.html

and at

http://perl.apache.org/docs/1.0/guide/troubleshooting.html

Let us know what the problem turned out to be in your case.

--Mike

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userSam Hathaway - Re: webserver dumping core  blueArrow
9/11/2005; 11:52:05 AM (reads: 782, responses: 0)
Apache will segfault if PHP's gd extension uses its own gd library AND mod_perl (or any other Apache module) loads the system gd library. The solution is to force PHP to link against the system gd library instead of using its own.

If you have PHP on the same server as WeBWorK, and PHP has the gd extension installed, run ldd on the gd extension (located somewhere like /usr/local/lib/php/20020429/gd.so) and see if it's linked against libgd. If it isn't, you will have trouble.

This can also be a problem with the PHP mysql extension -- it can similarly be built with an internal libmysqlclient or linked against the system's.

The solution, in both cases, is to specify a prefix for the library during PHP's configure phase: --with-gd=/usr/local or --with-mysql=/usr/local.
-sam

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userZbigniew Fiedorowicz - Re: webserver dumping core  blueArrow
9/18/2005; 8:27:53 AM (reads: 754, responses: 0)
Are there any other compiler switches for php which could cause this problem? Here is my php configuration information: './configure' '--with-mysql=/usr' '--with-apxs=/usr/local/apache/bin/apxs' '--enable-pic' '--with-bz2' '--with-curl' '--with-freetype-dir=/usr' '--with-png-dir=/usr' '--with-gd=/usr' '--enable-gd-native-ttf' '--with-ttf' '--with-gdbm' '--with-gettext' '--with-ncurses' '--with-gmp' '--with-iconv' '--with-jpeg-dir=/usr' '--with-openssl' '--with-png' '--with-zlib' '--enable-bcmath' '--with-imap=/usr/local/imap-2004a' '--with-imap-ssl' '--with-kerberos=/usr' '--with-ldap=shared' '--enable-memory-limit' '--enable-bcmath' '--enable-calendar' '--with-config-file-patch=/usr/local/apache/conf'

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userGavin LaRose - Re: webserver dumping core  blueArrow
9/19/2005; 8:52:50 AM (reads: 732, responses: 0)
One more follow-up: I'm not actually running PHP, so that shouldn't be the problem. After I corrected the directory permissions the problem seemed to back off, but I'm still getting a lot of coredumps. I'm going to go back through the log files today and see if I can see anything that would explain things.

Any other ideas are, of course, welcome.

Thanks,
Gavin

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