Re: AHCI bug: a lockup in ahci_interrupt with fbs enabled pmp

[Tejun Heo <tj@kernel.org>]

Cc'ing Shane.

On Thu, Jun 06, 2013 at 02:33:20PM +0800, Yu Liu wrote:
> Hi all,
> 
> I met a lockup while I was running IO test on disks connected
> with an fbs enabled pmp board and an ahci host.
> 
> looks like the reason for the lockup is as below:
>     ahci_interrert()
>         | spin_lock(&host->lock);                // get host->lock
>         | ahci_port_intr()
>             | ahci_error_intr()                  // status & PORT_IRQ_ERROR
>                 | ata_link_online()              // if fbs_enabled
>                     | sata_scr_read()
>                         | sata_pmp_scr_read()    // using pmp
>                             | ata_exec_internal()
>                                 | ata_exec_internal_sg()
>                                     | spin_lock_irqsave(ap->lock, flags);
> since ap->lock == &host->lock,
> these two spin_lock get conflict
> 
> Can someone confirm the issue? Did I miss anything?

Yeah, it's a bug.  ata_link_online() can't be called from interrupt
handlers.  Shane?  Can you please look into it?  What's the purpose of
ata_link_online() in ahci_error_intr()?

Thanks.

-- 
tejun