linux-kernel - Re: bio_integrity_verify() bug causing READ verify to be silently skipped

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Message-ID: <1389936047.5567.721.camel@haakon3.risingtidesystems.com>
Date:	Thu, 16 Jan 2014 21:20:47 -0800
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	"Martin K. Petersen" <martin.petersen@...cle.com>
Cc:	linux-scsi <linux-scsi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Jens Axboe <axboe@...nel.dk>, Christoph Hellwig <hch@....de>,
	Hannes Reinecke <hare@...e.de>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	kmo@...erainc.com
Subject: Re: bio_integrity_verify() bug causing READ verify to be silently
 skipped

On Fri, 2014-01-03 at 15:09 -0500, Martin K. Petersen wrote:
> >>>>> "nab" == Nicholas A Bellinger <nab@...ux-iscsi.org> writes:
> 
> nab> Given that bio_integrity_verify() is using bio_for_each_segment(),
> nab> the loop starts from the updated bio->bi_idx, and not a zero value,
> nab> which ends up skipping individual bio segment calls to
> nab> bi->verify_fn().
> 
> That's botched. Verify is meant to be called with the completed bytes
> before the index is tampered with.
> 
> 
> nab> The following patch changes bio_integrity_verify() to use
> nab> bio_for_each_segment_all() instead of bio_for_each_segment() to
> nab> ensure that the segment walk always starts from zero, regardless of
> nab> the current bio->bi_idx value after bio_advance().
> 
> That breaks partial completion, though. I'll take a look at Kent's
> changes...
> 

Ping..?  Any updates on a proper bugfix for this..?

--nab

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