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Author Topic: .CORE files - HOw to STOP THEM!  (Read 38486 times)

Offline pooya

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.CORE files - HOw to STOP THEM!
« on: November 20, 2008, 08:11:37 PM »
Guys i got joomla running on my main root.

Everyday .core files are made on its own, im guessing youll know what they are.

Now my host says he has no clue what they about and says my joomla is doing it cause  to him its only my site creating the core files.

Has anyone any knowledge to this ? i searched joomla but all i found is some termination of a service on host causing this..

Completely lost, help.

Offline 青山 素子

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Re: .CORE files - HOw to STOP THEM!
« Reply #1 on: November 21, 2008, 01:15:54 AM »
Core files are created when a program on the server crashes. Now, it is true that your site is causing the crash. However, normal PHP code has no ability to cause that kind of crash on its own. Core files are a symptom of a problem on the server.

Your host has the ability to determine what exactly is causing the crash by running a tool called gdb on one of those files. That should tell them the exact program crashing and even perhaps why.
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #2 on: November 21, 2008, 06:53:40 AM »
Thankyou very much motoko.. ill let my host know **reseller lol..

Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #3 on: November 21, 2008, 02:05:10 PM »
Reply of my host :

Problem: your account is the only one creating core dumps. I have about 200 accounts on the other server, not a single core file. I can't look into the crashed processes as the processes are already terminated, there's no logging of historical processes.

Offline 青山 素子

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Re: .CORE files - HOw to STOP THEM!
« Reply #4 on: November 21, 2008, 05:37:05 PM »
Well, if the site seems to run fine otherwise, just delete the files when you see them. If the host refuses to do a thing, there isn't much you can do besides finding a new host.

Also, you could try disabling hostname lookups. I've seen some bugs with the default RedHat PHP and the host command that can cause segfaults (and core dumps like you are seeing). Of course, they should be updating the box to the fixed versions...

Also, moving to server support, as this is really a support topic.
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Offline CoreISP

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Re: .CORE files - HOw to STOP THEM!
« Reply #5 on: November 21, 2008, 06:16:28 PM »
What exactly shows in the error logs?

It could be a bad PHP script too you know.
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Offline 青山 素子

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Re: .CORE files - HOw to STOP THEM!
« Reply #6 on: November 21, 2008, 07:29:55 PM »
If it was a bad PHP script, it should be throwing PHP errors. If it is getting PHP or another app to crash, it's 99.999% of the time an issue in that app or a library.
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #7 on: November 22, 2008, 06:47:10 AM »
Well to be honest my joomla php is truely messed up..

But like motoko says its a server error , but my host says its just my site :(

ALso  these files are over 28mb each ... upto 32mb.

Offline CoreISP

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Re: .CORE files - HOw to STOP THEM!
« Reply #8 on: November 22, 2008, 09:23:07 AM »
Yeah... is it by any chance a 500 internal server error that creates the .CORE files?
That can still be the cause of a bad PHP script.
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #9 on: November 23, 2008, 09:05:53 AM »
THe 500 internal server error dosent show up anywhere on my site :(

All i have is 404 redirects lol, but thats totally different.

:( so lost and my host is more lost then i am.

Offline CoreISP

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Re: .CORE files - HOw to STOP THEM!
« Reply #10 on: November 23, 2008, 09:54:57 AM »
So what's in the error logs?
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #11 on: November 23, 2008, 03:08:08 PM »
The .core error or the error log file the server generates ?


Offline expresscolo-tom

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Re: .CORE files - HOw to STOP THEM!
« Reply #12 on: November 24, 2008, 04:46:24 PM »
I happened to be reading the forums for another customer trying to find an answer to their problem, and I saw this post and I had to create a login just to reply to it....

It saddens me that a hosting provider doesn't know what a core file is or how to properly handle them. They are actually fairly invaluable sources of information; often giving you a great deal of information into why something crashes and provide a great deal of detail as to exactly what crashed and why.

To answer your question... the best way to get rid of them is to fix the problem that is causing them.

You need to identify what process is actually creating them. Most likely since this is a web server, I would lean towards apache/httpd, but you can't always trust intuition. Fortunately you can use the app 'file' to help you with this information. You just need to type:

"file core.1234"

at the command line and it will tell you what application created the core file.

then you can run:

"gdb httpd core.1234" (assuming the core was created by the httpd process)

That will provide you a stack of the application as it was running when it segfaulted and dumped this core file. Using this information you would be able to determine what caused the application to segfault in the first place.

Using this information your provider should be able to properly diagnose the problem and fix it.

The other... uglier option, is to turn off core dumps in the OS, and apache.


Offline metallica48423

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Re: .CORE files - HOw to STOP THEM!
« Reply #13 on: November 24, 2008, 05:27:27 PM »
Keep in mind that in many cases you will need shell/SSH access to do the above

Though, if joomla is causing these problems, have you considered contacting the folks at joomla?  It may be, perhaps, a known issue with a certain setting which can cause this.
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Offline expresscolo-tom

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Re: .CORE files - HOw to STOP THEM!
« Reply #14 on: November 24, 2008, 07:30:17 PM »
I should have been more specific... in that my recommendation was to be provided to the hosting provider via the OP, not that the OP would run those specific commands. They generally require root permission to a certain degree.

Offline metallica48423

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Re: .CORE files - HOw to STOP THEM!
« Reply #15 on: November 25, 2008, 12:00:38 AM »
of course :)

I'm more than not making a note for anyone who might find that post in the future -- this forum also doubles as a searchable support database ;) -- That is, we don't remove old posts and topics
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #16 on: November 25, 2008, 02:31:36 PM »
Awesome post express.. Im forwading this to my host hoping it finds a cure.

metallica i search on joomla, they said there script cant be possible making .core files as its a server related command and no php can do so ...

Offline 青山 素子

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Re: .CORE files - HOw to STOP THEM!
« Reply #17 on: November 25, 2008, 06:15:54 PM »
metallica i search on joomla, they said there script cant be possible making .core files as its a server related command and no php can do so ...

Well... It certainly isn't their script, but there could be some library PHP uses for a certain command, which just happens to be something their script calls. Likewise for SMF. So, yes, a PHP script can cause a core dump to happen. However, it isn't the problem, but rather it exposes a problem with one of the underlying things it uses.

I know one issue was a bad version of the "host" command on some CentOS/RHEL/Fedora machines that would coredump when being used. This was fixed, and the host should have updated their server since then, getting a fixed edition, but some still have not done so (and are very insecure since there have been security patches for the OS since then!).
« Last Edit: November 25, 2008, 06:17:36 PM by Motoko-chan »
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Offline CoreISP

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Re: .CORE files - HOw to STOP THEM!
« Reply #18 on: November 26, 2008, 05:12:06 AM »
To answer your question... the best way to get rid of them is to fix the problem that is causing them.

Lol, i'm going to remember that one as the universal answer to everything.
No offence by the way :P
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Offline pooya

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Re: .CORE files - HOw to STOP THEM!
« Reply #19 on: November 26, 2008, 12:31:52 PM »
Hey buddy,

Lol, this company sounds like it's quite upset with this whole core file issue :) the reason i don't know what it is and how to handle them is cause i've never seen them before - i guess i've never had such poorly written software running on my servers before ;)

so yeah, here's the output:
root@power [/home/xxxt/public_html]# file core.10213
core.10213: ELF 64-bit LSB core file AMD x86-64, version 1 (SYSV), SVR4-style, from 'w}'

as for gdb - says command not found.

Feel free to advise further, since these guys are pros with dealing with running their buggy software on reliable webservers ;)


***Sounds like host is fired up :P