linux-kernel - RE: sata_mv port lockup on hotplug (kernel 2.6.38.2)

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Message-ID: <C1438B59050E1B4C9482FF3266AD6BA32C775549E4@gretna.indigovision.com>
Date:	Mon, 25 Apr 2011 15:54:38 +0100
From:	Bruce Stenning <b.stenning@...igovision.com>
To:	Tejun Heo <htejun@...il.com>, Mark Lord <kernel@...savvy.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-ide@...r.kernel.org" <linux-ide@...r.kernel.org>
Subject: RE: sata_mv port lockup on hotplug (kernel 2.6.38.2)

Tejun wrote:

> Yeap, devices behind SATA-PATA bridge were still affected by the transfer
> mode so libata tries to slow them down too along with link speed when
> limiting speed due to errors.  Shouldn't affect native SATA devices.

Thanks.

I wrote:

> 00040055
> 00040015
> __ata_port_freeze: ata4 port frozen
> ata_port_schedule_eh: port EH scheduled
> ata_eh_thaw_port: ata4 port thawed
> ata_std_postreset: ENTER
> ata4: SATA link down (SStatus 0 SControl 310)
> ata_std_postreset: EXIT
> ata_eh_revalidate_and_attach: ENTER
> ata_eh_revalidate_and_attach: EXIT rc=-5
> ata4.00: disabled
> ata_eh_revalidate_and_attach: ENTER
> ata_eh_recover: EXIT, rc=0
> ata4: EH complete
> ata_scsi_error: EXIT
> ata_scsi_hotplug: ENTER
> ata4.00: detaching (SCSI 3:0:0:0)
> ata_scsi_hotplug: EXIT

Okay, so the ata_eh_thaw_port has raced (and won) against whatever was in the
process of masking off the irq (the __ata_port_freeze?), which then completes
leaving libata/sata_mv thinking the port is thawed while no further irqs get
generated.

Could ata_port_freeze or __ata_port_freeze (which don't claim the ap's lock)
have been invoked and then slept while ata_eh_thaw_port runs?


Bruce.


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