From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jeff@garzik.org>
Subject: Re: WARN_ON() in drivers/ata/libata-core.c:5211 ata_qc_issue
Date: Tue, 20 Apr 2010 21:55:09 -0400
Message-ID: <4BCE5AFD.4030108@garzik.org>
References: <20100420141616.GP4586@mail.wantstofly.org> <4BCE43FD.1080303@gmail.com>
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To: Robert Hancock <hancockrwd@gmail.com>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>, Andy Yan <ayan@marvell.com>, Ke Wei <kewei@marvell.com>, Ying Chu <jasonchu@marvell.com>, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org
List-Id: linux-scsi@vger.kernel.org

On 04/20/2010 08:17 PM, Robert Hancock wrote:
> On 04/20/2010 08:16 AM, Lennert Buytenhek wrote:
>> On mvsas, when I issue a SMART command (smartctl -a) while a dd
>> from /dev/sda to /dev/null is in progress, I hit the following
>> WARN_ON_ONCE in ata_qc_issue():
>>
>> if (ata_is_ncq(prot)) {
>> WARN_ON_ONCE(link->sactive& (1<< qc->tag));
>>
>> if (!link->sactive)
>> ap->nr_active_links++;
>> link->sactive |= 1<< qc->tag;
>> } else {
>> WARN_ON_ONCE(link->sactive); <===============
>>
>> ap->nr_active_links++;
>> link->active_tag = qc->tag;
>> }
>>
>> This is on 2.6.34-rc4 ish.
>
> That would indicate that for some reason, non-NCQ commands aren't being
> deferred while an NCQ command is in progress. Presumably something wrong
> in mvsas or libsas code in general..

Yep, definitely a problem in the mvsas (or libsas) area.

	Jeff