ETOOMANYREFS related errors

[Luis Ugalde]

Hi,

I've been running a Debian-Jessie backported 4.4 kernel for the last few
days, and I can confirm the same issue happening with this kernel as well.

Regards,
Luis

El vie., 11 mar. 2016 a las 9:01, Luis Ugalde (<forondarena at gmail.com>)
escribió:

> 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.
>