[clug] Segfault error flooding my logs

[David Schoen]

I'm not sure about the terminology or the exact process, but the
apache parent process definitely starts off a new child worker and
forgets about the old one (not sure if it needs to or does any other
cleaning up).

I've seen _a lot_ of segfaulting apache threads, the only time it's
ever caused an immediately noticeable problem (as in someone not
grepping logs being able to tell it's broken) was on a Solaris box
that was configured to collect segfault core dumps in /var/core, the
file system fails and then normal havoc ensues.

I think normally you will just get something in syslog like you've
attached and there should be something in the apache error log about
having lost a child when it comes back to use that proc (can't
remember the exact error though), depending on your request volume
this entry might not be any where near the segfault time stamp.

If it's concerning* enough you should look at your relevant access log
at the time when php was segfaulting to try and determine what
request(s) are failing it.

Cheers,
Dave

* if this box is in any way connected to the same internet I'm
connected to, I'd be concerned.

2009/8/31 David Tulloh <david at tulloh.id.au>:
> PCRE has numerous well known and documented segfault problems, PHP makes no
> attempt to catch or filter these out.
>
> Apache forks off a new worker thread* for each request that comes in, when
> PCRE segfaults this thread dies. Apache however carries on, so your server
> will not go down if a few threads do. I'm not sure if these segfaulted
> threads are cleaned up or hang around, if it's the latter your server may
> eventually stop responding as it runs out of threads.
>
>
> David
>
> * Assuming default Apache 2 configuration with mpm-worker model, other
> models will vary slightly in effects.
>
> Ian McLeod wrote:
>>
>> Thanks for this..
>>
>> My Cacti server is still working though..
>>
>> Andrew Janke wrote:
>>
>>>
>>> On Mon, Aug 31, 2009 at 18:36, Andrew Janke<a.janke at gmail.com> wrote:
>>>
>>>>
>>>> Not that this helps but you are not alone.
>>>>
>>>> https://bugs.launchpad.net/ubuntu/+source/pcre3/+bug/296997
>>>>
>>>
>>> And more pertinently.
>>>
>>> https://bugs.launchpad.net/ubuntu/+source/php5/+bug/407248
>>>
>>> a
>>>
>
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