[squid-users] assertion failed: Controller.cc:930: "EX"

[Gaetano]

Thank you Alex for your prompt feedback!

Cheers,
Gaetano

On Mon, Nov 18, 2024 at 3:21 AM Alex Rousskov
<rousskov at measurement-factory.com> wrote:
>
> On 2024-11-17 18:41, Gaetano wrote:
>
> > We are running three squid proxy 5.5,
>
> Please note that Squid Project does not support Squid v5. I recommend
> upgrading to Squid v6+ (regardless of what your Linux distribution
> currently ships).
>
>
> > on three different VMs, same
> > number of CPUs (4), same memory, and same FS type (xfs) on Alma Linux
> > 9.
> > All servers are staged with Ansible and they all have the same squid.conf.
> >
> > workers 4
> > ...
> > cache_dir ufs /var/spool/squid 512 16 256
>
> As you probably know from that earlier thread, this combination is not
> supported and is likely to trigger HTTP violations and undefined
> behavior. The only supported cache_dir type for SMP Squids is rock.
>
>
> > One of those servers (always the same) crashes with this assert:
> >   kid1| assertion failed: Controller.cc:930: "EX"
> > kid can be from 1 to 4
>
> BTW, that bogus exception text "EX" is a bug. It was fixed in Squid v6.
> Squid v5.10 has a backport of that fix.
>
>
> > Everything works fine when we remove workers as explained in an old
> > post about ufs and multithreading:
> > https://lists.squid-cache.org/pipermail/squid-users/2021-November/024285.html
> >
> > However, why don't the other two proxies suffer from the same issue?
> >
> > Removing  /var/spool/squid/* (+ squid -z) makes things work for a
> > little while, then again Empty response from the server (=> assertion
> > failed: Controller.cc:930: "EX").
> > So somehow it seems related to the cache and/or the response.
> >
> > Any ideas that could help to understand the problem?
>
> I cannot help with understanding why undefined Squid behavior in an
> unsupported configuration manifests itself this particular way, but I
> hope that switching to a supported version and configuration helps avoid
> this problem.
>
>
> Good luck,
>
> Alex.
>