Re: [squid-users] FATAL bus error but no core - suggestions?

On Tuesday 13 May 2003 21.49, Adam wrote:

> Last week squid crashed around 8am (usage is moderate, not high at
> that hour) on my PROD box with the error " FATAL: xmalloc: Unable
> to allocate 24576 bytes!" Per the FAQ it can either be a lack of
> swap or "maximum data segment size." Since ulimit reports
> unlimited for that, I am assuming that swap becomes in short
> supply.

Actually process size is limited by more factors than only ulimit.
"unlimited" just means "as large as this kernel can handle".

> swap is rare. Will making ondisk swap 1GB help?

Maybe, maybe not. It depends on the actual reason to why malloc()
reported out of memory.

Monitoring the size of your Squid process is probably advisable.

> What happened today was squid crashed with the error "FATAL:
> Received Bus Error...dying." which, according to the three threads
> I found on the mailing list, would indicate a bug (FAQ shows how to
> analyze the core).

Indeed.

> able to restart itself but I am wondering if there is something
> else I need to do to enable core creation for squid. I doubt it
> but am posting, just in case. I haven't disabled core creation
> (i.e. using coreadm or anything). Server is an Ultra 60, 1GB of
> RAM, Solaris 8, Squid 2.5STABLE2.

If you start Squid as root then you probably need to reconfigure your
OS to enable coredumps to allow applications like Squid to generate a
core. Normally coredumps of daemons started as root but which have
later changed their user id to a non-privileged user is disabled by
default for security reasons (if not this non-privileged user may be
able to steal information via the core dump only root should have
access to)

If you want coredumps then it is best to start Squid as the
cache_effective_user, not as root. This will on most OS:es allow core
dumps to be generated, subject to your ulimit setting when starting
Squid, without having to give permssion via coreadm or other OS
configuration.

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