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From: Jason Gunthorpe <jgg@ziepe.ca>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-integrity@vger.kernel.org,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Peter Huewe <peterhuewe@gmx.de>
Subject: Re: [PATCH] tpm_tis: Add a check for invalid status
Date: Mon, 28 Sep 2020 15:33:51 -0300	[thread overview]
Message-ID: <20200928183351.GA587339@ziepe.ca> (raw)
In-Reply-To: <9bad3da0c31ae2620aaae0d75748c3387afa3d47.camel@HansenPartnership.com>

On Mon, Sep 28, 2020 at 11:00:12AM -0700, James Bottomley wrote:
> Some TIS based TPMs can return 0xff to status reads if the locality
> hasn't been properly requested.  Detect this condition by checking the
> bits that the TIS spec specifies must return zero are clear and return
> zero in that case.  Also drop a warning so the problem can be
> identified in the calling path and fixed (usually a missing
> try_get_ops()).
> 
> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> 
> This is the patch I've been using to catch and kill all the points in
> the stack where we're not properly using get/put ops on the tpm chip.

If this is a problem add a lockdep on ops_sem in various places too?

Jason

  reply	other threads:[~2020-09-28 18:33 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-28 18:00 [PATCH] tpm_tis: Add a check for invalid status James Bottomley
2020-09-28 18:33 ` Jason Gunthorpe [this message]
2020-09-28 21:15   ` James Bottomley
2020-09-30  1:37     ` Jarkko Sakkinen
2020-09-30  1:40       ` Jarkko Sakkinen

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