Re: linux-next: Tree for December 11

[Ingo Molnar]

* Alexey Zaytsev <alexey.zaytsev@xxxxxxxxx> wrote:

> On Wed, Dec 17, 2008 at 00:08, Ingo Molnar <mingo@xxxxxxx> wrote:
> 
> >>
> >> The warning can also be reproduced in qemu, so it was easy to bisect.
> >>
> >> commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd
> >> Author: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
> >> Date:   Tue Sep 30 20:50:27 2008 +1000
> >>
> >>     sched: improve preempt debugging
> >>
> >>     This patch helped me out with a problem I recently had....
> >>
> >>     Basically, when the kernel lock is held, then preempt_count
> >> underflow does not
> >>     get detected until it is released which may be a long time (and arbitrarily,
> >>     eg at different points it may be rescheduled). If the bkl is released at
> >>     schedule, the resulting output is actually fairly cryptic...
> >>
> >>     With any other lock that elevates preempt_count, it is illegal to schedule
> >>     under it (which would get found pretty quickly). bkl allows scheduling with
> >>     preempt_count elevated, which makes underflows hard to debug.
> >>
> >>     Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> >>
> >> I understand that not this particular commit is buggy, but at least
> >> I've got someone to add to the CC. ;)
> >>
> >> Also the author's e-mail looks suspicious.
> >
> > Suspicious in what way?
> 
> Does not appear in signed-off-by.

yes, because i applied and tested it through before Nick was comfortable 
with signing off on it.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/