ETOOMANYREFS related errors

[Luis Ugalde]

El vie., 11 mar. 2016 a las 2:08, Timo Sirainen (<tss at iki.fi>) escribió:

> On 11 Mar 2016, at 03:48, Luis Ugalde <forondarena at gmail.com> wrote:
> >
> > Hi,
> >
> > I'm starting to see, on a pretty standard Debian Jessie installation,
> some
> > error messages that are apparently related to the ETOOMANYREFS errno.
> >
> > Firstly, the mail log shows this:
> > dovecot: pop3-login: Error: fd_send(pop3, 18) failed: Too many
> references:
> > cannot splice
>
> Apparently because Linux thinks the same fd has been passed around
> recursively too many times:
> http://lkml.iu.edu/hypermail/linux/kernel/1101.0/01917.html
>
> But Dovecot doesn't pass it recursively. It's only passed once from
> pop3-login to pop3 process.
>
> > Is this something that Dovecot should be able to handle, or is it
> strictly
> > Debian/libc/MySillyMistake related?
> >
> > #uname -a
> > Linux server 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt20-1+deb8u3
> > (2016-01-17) x86_64 GNU/Linux
>
> I wonder if there's a new kernel change that started detecting the
> recursion wrong.
>
>
Yes, It's started to happen with the latest kernels from the Stable branch.
This is the latest I have installed:
3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt20-1+deb8u3 (2016-01-17) x86_64

Older Debian kernels are not showing up anything. This one, for example:
 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64


Regards.