From: ebiederm@xmission.com (Eric W. Biederman)
To: Dave Jones <davej@redhat.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: kernel: sysctl table check failed: /dev/parport/parport0/devices/ppdev0/timeslice Sysctl already exists
Date: Fri, 30 May 2008 11:19:28 -0700 [thread overview]
Message-ID: <m1wslb1wpb.fsf@frodo.ebiederm.org> (raw)
In-Reply-To: <20080530150515.GA30397@redhat.com> (Dave Jones's message of "Fri, 30 May 2008 11:05:15 -0400")
Dave Jones <davej@redhat.com> writes:
> Well, that's umm, special.
> I wonder if powering off the printer isn't causing the sysctl to be removed,
> causing the next power-on to look like a new device ?
> Eric, you poked around the sysctl paths in parport last year, any ideas?
Yes. The short answer is that this is a real bug in the parport code
that has existed forever. We just now complain.
http://bugzilla.kernel.org/show_bug.cgi?id=9749
It takes something like two accessors of the parallel port to trigger
this. Though not in a bad way.
In particular each open creates the sysctl for the duration of the
open (or something like that) and so if you open (I think it is
/dev/parport0) twice you try and create the sysctls twice.
I got as far as basic confirmation of this bug, and a rough cause of
it. Unfortunately I have not had the time to unscramble it, and neither
it seems has anyone else.
Eric
prev parent reply other threads:[~2008-05-30 18:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-30 15:05 kernel: sysctl table check failed: /dev/parport/parport0/devices/ppdev0/timeslice Sysctl already exists Dave Jones
2008-05-30 18:19 ` Eric W. Biederman [this message]
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