2012-11-05 19:42:46

by Alexander Holler

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Subject: connector and netlink_broadcast (semop failed for cookie ...)

Hello,

I've recently enabled CONFIG_CONNECTOR in kernel 3.6.6 and now I've got
the message "semop failed for cookie ..." when using cryptsetup (I've
never got that error before).

A short search revealed the following discussion about ignoring errors
from netlink_broadcast_filtered(): https://lkml.org/lkml/2011/8/19/60

connector doesn't use netlink_broadcast_filtered() directly but it
returns netlink_broadcast() in cn_netlink_send() while
netlink_broadcast() just is a wrapper around netlink_broadcast_filtered().

Could it be the case that cn_netlink_send() has to ignore the same
return codes as done in kobject_uevent_env()? Or maybe the users of
cn_netlink_send() have to ignore them?

Regards,

Alexander


2012-11-05 21:12:03

by Evgeniy Polyakov

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Subject: Re: connector and netlink_broadcast (semop failed for cookie ...)

Hi

On Mon, Nov 05, 2012 at 08:42:32PM +0100, Alexander Holler ([email protected]) wrote:
> Could it be the case that cn_netlink_send() has to ignore the same
> return codes as done in kobject_uevent_env()? Or maybe the users of
> cn_netlink_send() have to ignore them?

We just do not know what to do with that error.
Pretty much it means nothing can be done about it.
There is no recovery path, no collection and resend, since it may lead to dos.

Its like knowing that udp packet get lost, but you do not have enough
buffer space to save it and block. Actually there is no buffer at all.
Kind of missed interrupt.

--
Evgeniy Polyakov