Re: block: BUG: using smp_processor_id() in preemptible [00000000] code

From: Ming Lei
Date: Tue Jul 26 2011 - 02:22:50 EST


Hi,

On Tue, Jul 26, 2011 at 1:26 PM, Jens Axboe <jaxboe@xxxxxxxxxxxx> wrote:
> On 2011-07-26 06:49, Ming Lei wrote:
>> Hi,
>>
>> The bug is observed in -next-20110725, follows the stack trace[1], and
>> seems the attachment patch can fix the bug.
>
> Does this work, too? We don't necessarily need the CPU stable, but
> spewing debug output isn't very nice.

This does work, thanks,

> diff --git a/block/blk-core.c b/block/blk-core.c
> index f8cb099..f925581 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1283,7 +1283,7 @@ get_rq:
>
>        if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) ||
>            bio_flagged(bio, BIO_CPU_AFFINE))
> -               req->cpu = smp_processor_id();
> +               req->cpu = raw_smp_processor_id();
>
>        plug = current->plug;
>        if (plug) {
>
> --
> Jens Axboe
>
>


thanks,
--
Ming Lei
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