From: Nick Piggin <npiggin@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Alexey Zaytsev <alexey.zaytsev@gmail.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Laurent Riffard <laurent.riffard@free.fr>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: next-20090107: WARNING: at kernel/sched.c:4435 sub_preempt_count
Date: Wed, 14 Jan 2009 03:00:40 +0100 [thread overview]
Message-ID: <20090114020040.GA19806@wotan.suse.de> (raw)
In-Reply-To: <20090111024945.GC7077@elte.hu>
On Sun, Jan 11, 2009 at 03:49:45AM +0100, Ingo Molnar wrote:
>
> * Alexey Zaytsev <alexey.zaytsev@gmail.com> wrote:
>
> > One more instance of http://marc.info/?l=linux-kernel&m=123134586202636&w=2
> > Added Ingo Molnar to CC.
>
> added Nick on Cc:. Nick, it's about:
>
> > commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd
> > Author: Nick Piggin <nickpiggin@yahoo.com.au>
> > Date: Tue Sep 30 20:50:27 2008 +1000
> >
> > sched: improve preempt debugging
>
> causing a seemingly spurious warning.
I don't know how it is spurious... Presumably the sequence _would_ have
caused preempt count to go negative if the bkl were not held...
__do_softirq does a __local_bh_disable on entry, and it seems like the
_local_bh_enable on exit is what causes this warning. So something is
unbalanced somehow. Or is it some weird thing we do in early boot that
I am missing?
Can you put in some printks around these functions in early boot to
get an idea of what preempt_count is doing?
next prev parent reply other threads:[~2009-01-14 2:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-08 23:17 next-20090107: WARNING: at kernel/sched.c:4435 sub_preempt_count Laurent Riffard
2009-01-09 10:09 ` Alexey Zaytsev
2009-01-11 2:49 ` Ingo Molnar
2009-01-14 2:00 ` Nick Piggin [this message]
2009-01-18 18:22 ` Alexey Zaytsev
2009-01-18 18:24 ` Ingo Molnar
2009-01-18 18:24 ` Alexey Zaytsev
2009-01-25 0:33 ` Alexey Zaytsev
2009-01-26 14:43 ` Ingo Molnar
2009-01-26 14:53 ` Alexey Zaytsev
2009-01-26 15:09 ` Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090114020040.GA19806@wotan.suse.de \
--to=npiggin@suse.de \
--cc=a.p.zijlstra@chello.nl \
--cc=alexey.zaytsev@gmail.com \
--cc=laurent.riffard@free.fr \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.