Re: linux-next: Tree for December 11

[Alexey Zaytsev]

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.

>
>        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/