From: Jeff Garzik <jgarzik@pobox.com>
To: Tejun Heo <htejun@gmail.com>
Cc: linux-ide@vger.kernel.org, albertcc@tw.ibm.com
Subject: Re: [PATCH 09/13] libata: fix handling of race between timeout and completion
Date: Thu, 26 Jan 2006 22:58:56 -0500 [thread overview]
Message-ID: <43D99A80.1060904@pobox.com> (raw)
In-Reply-To: <43D999CF.7020707@pobox.com>
Jeff Garzik wrote:
> Tejun Heo wrote:
>
>> If a qc completes after SCSI timer expires but before libata EH kicks
>> in, the qc gets completed but the scsicmd still gets passed to libata
>> EH resulting in ->eng_timeout invocation with NULL qc. Currently none
>> of ->eng_timeout callbacks handles this properly. This patch makes
>> ata_scsi_error() bypass ->eng_timeout and handle this rare case.
>>
>> Signed-off-by: Tejun Heo <htejun@gmail.com>
>
>
> Doesn't look right to me. If the qc gets completed, then the SCSI
> command should have also been completed.
>
> AFAICS the race is this: if the qc is completed, then there is no
> active tag, so ata_qc_from_tag() correctly returns NULL. This case is
> really an "error has already been handled" case. It looks really wrong
> to even touch a scsicmd. I would just clear the eh_cmd list and be done
> with it.
dropped patches 9-10
next prev parent reply other threads:[~2006-01-27 3:59 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-23 4:09 [PATCHSET] libata: various fixes related to EH, take #2 Tejun Heo
2006-01-23 4:09 ` [PATCH 01/13] libata: fold __ata_qc_complete() into ata_qc_free() Tejun Heo
2006-01-27 3:34 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 07/13] SCSI: export scsi_eh_finish_cmd() and scsi_eh_flush_done_q() Tejun Heo
2006-01-23 7:09 ` Jeff Garzik
2006-01-23 7:26 ` Arjan van de Ven
2006-01-23 8:20 ` Tejun Heo
2006-01-23 9:36 ` Christoph Hellwig
2006-01-23 10:05 ` Tejun Heo
2006-01-24 17:11 ` Luben Tuikov
2006-01-24 17:20 ` Arjan van de Ven
2006-01-24 18:25 ` Luben Tuikov
2006-01-24 17:30 ` Jeff Garzik
2006-01-24 18:53 ` Luben Tuikov
2006-01-23 14:52 ` Tejun Heo
2006-01-23 4:09 ` [PATCH 06/13] libata: return AC_ERR_* from issue functions Tejun Heo
2006-01-23 4:09 ` [PATCH 05/13] libata: add detailed AC_ERR_* flags Tejun Heo
2006-01-23 4:09 ` [PATCH 04/13] ahci: fix err_mask setting in ahci_host_intr Tejun Heo
2006-01-27 3:36 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 03/13] libata: fix ata_qc_issue() error handling Tejun Heo
2006-01-23 4:09 ` [PATCH 02/13] libata: make the owner of a qc responsible for freeing it Tejun Heo
2006-01-23 4:09 ` [PATCH 13/13] libata: EH / pio tasks synchronization Tejun Heo
2006-01-23 4:09 ` [PATCH 10/13] libata: kill NULL qc handling from ->eng_timeout callbacks Tejun Heo
2006-01-23 4:09 ` [PATCH 12/13] libata: create pio/atapi task queueing wrappers Tejun Heo
2006-01-27 4:02 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 11/13] libata: implement ATA_FLAG_IN_EH port flag Tejun Heo
2006-01-27 4:00 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 09/13] libata: fix handling of race between timeout and completion Tejun Heo
2006-01-27 3:55 ` Jeff Garzik
2006-01-27 3:58 ` Jeff Garzik [this message]
2006-02-01 15:36 ` Tejun Heo
2006-02-09 6:21 ` Jeff Garzik
2006-01-23 4:09 ` [PATCH 08/13] libata: implement and apply ata_eh_qc_complete/retry() Tejun Heo
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