Re: WARNING: at drivers/ata/libata-core.c:5988 ata_qc_issue()

[Mark Lord <liml@rtr.ca>]

Tejun Heo wrote:
> Mark Lord wrote:
>> Tejun,
>>
>> During testing with NCQ on sata_mv (patches coming shortly),
>> I found this gem in the syslog.  This doesn't look like something
>> that a LLD could cause, but rather a race perhaps in libata-core.
> 
> Hmmm... This isn't supposed to happen.
> 
>> System is a 2.4GHz 32-bit Core2Quad, 2GB RAM (during this test),
>> running 2.6.24-rc6-git12 + newer sata_mv, with two sata_mv controller
>> cards, each with one NCQ drive performing heavy R/W activity.
>>
>> Other than that, I'm not sure what triggered this.
> 
> Can you please tell me which version you were using?  Or tell me which
> one of the three WARN_ON()'s in ata_qc_issue() was triggered?  Thanks.
..
>> [  289.892890] WARNING: at drivers/ata/libata-core.c:5988 ata_qc_issue()
..

The first one shown below, at drivers/ata/libata-core.c:5988:

> void ata_qc_issue(struct ata_queued_cmd *qc)
> {
>         struct ata_port *ap = qc->ap;
>         struct ata_link *link = qc->dev->link;
> 
>         /* Make sure only one non-NCQ command is outstanding.  The
>          * check is skipped for old EH because it reuses active qc to
>          * request ATAPI sense.
>          */
=         WARN_ON(ap->ops->error_handler && ata_tag_valid(link->active_tag));
> 
>         if (qc->tf.protocol == ATA_PROT_NCQ) {
>                 WARN_ON(link->sactive & (1 << qc->tag));
> 
..