[CentOS] Cron script crashing server...

Ian mu mu.llamas at gmail.com
Tue Oct 4 13:37:42 UTC 2005


Hiya, just wanted to say thanks, will leave it at that and do some debugging
I think :).
 Cheers all, Ian

 On 10/4/05, Mark Belanger <mark_belanger at ltx.com> wrote:
>
> Ian mu wrote:
> > Hiya, redid the crontab file and still crashed, had the strace running
> > on it and compared the run without cron to the run from cron. It does
> > actually run the stats script so was misleading before, so I'm guessing
> > previously just hadn't got as far as outputting it to file or something.
>
> Hmm,,, if you're echoing in the stats script it should show up
> some place.
>
> > Crashing server from cron strace, 10297 is the script, 10296 is a mrtg
> > running from a different account which runs fine whatever...
>
> First off, I'd remove mrtg from the equation(cron) and strip it down
> to just your program.
>
> I guess then I'd focus on the portion of your script that
> follows "### MODS ##################".
>
> You might try different strace flags - make sure you are following
> all forks.
>
> One trick I've used before is to replace the call to
> the perl program in the stats script to open up the program
> inside the perl debugger. For instance, if the stats
> script is running
> /usr/local/bin/myscript.pl
> You could change it to:
> typeset -x DISPLAY=mydisplay:0
> xterm -e 'perl -d /usr/local/bin/myscript.pl'
>
> Once it comes up, you can just continue to see if the
> crash happens and if so you could step through the code
> until you find the offending lines. If you're a "debug with print"
> kind of guy you could still do the xterm trick but just insert
> sleeps and prints into the perl program to narrow down
> the exact line that is causing the problem. After realize how
> much time was wasted with print statements, you can spend a couple
> of hours learning the perl debugger :)
>
> I'm afraid I'm running out of helpful(and intelligent)
> feedback on this problem. One thing I did notice, the mrtg script
> seemed to go through a fair amount of gyrations to find
> integer.pm <http://integer.pm> - though it's probably not related to the
> problem.
>
> >
> > 10297 read(4, ",\n \'*\' => \'ae181a\',\n "..., 4096) = 4096
> > 10297 read(4, ">[0] eq \'COMT\' and $r >= $floor;"..., 4096) = 4096
> > 10297 brk(0) = 0x870a000
> > 10297 brk(0x872b000) = 0x872b000
> > ENOENT (No such file or directory)
> > -1 ENOENT (No such file or directory)
> > file or directory)
> > such file or directory)
> > 0xbfff9ba0) = -1 ENOENT (No such file or directory)
> > O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
> > (No such file or directory)
> > (Inappropriate ioctl for device)
> > 10297 read(4, <unfinished ...>
> > 10297 <... read resumed> "\n}\n\n### MODS ###################"..., 4096)
> > = 3988
> > = 3266
> > 10297 read(4, "", 4096) = 0
> > 10297 close(4) = 0
> > 10297 open("", O_RDONLY|O_LARGEFILE <unfinished ...>
> > <strace stopped here>
>
> -Mark
>
>
> --
> Mark Belanger
> LTX Corporation
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