linux-kernel - Re: [PATCH 1/5] tpm: Trigger only missing TPM 2.0 self tests

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Message-ID: <20180305112334.GI25377@linux.intel.com>
Date:   Mon, 5 Mar 2018 13:23:34 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     James Bottomley <James.Bottomley@...senPartnership.com>
Cc:     linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        Alexander Steffen <Alexander.Steffen@...ineon.com>,
        stable@...r.kernel.org,
        Jarkko Sakkinen <jarkko.sakkine@...ux.intel.com>,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/5] tpm: Trigger only missing TPM 2.0 self tests

On Sat, Mar 03, 2018 at 12:11:59PM -0800, James Bottomley wrote:
> I still think removing all logging traces is a mistake for something
> that can consume a significant amount of time in the boot sequence.
>  It's going to cause lost of people doing boot timings to waste lots of
> effort.
> 
> However, removing the log messages makes the above statement a lie, so
> one of the two needs fixing.

The commit itself makes sense but the implementation was sloppy to say
the least in v3. It was like prototype/PoC version of something that
could be merged to mainline, not something that can be merged to
mainline.

For example:

* You could have implemented it more cleanly without that new
  'tpm_transmit_check' helper function as can be seen.
* Many log messages contained a redundant "TPM:" prefix.
* There duplicate logs to tpm_transmit_cmd(). Pass a NULL as
  desc tpm_transmit_cmd() if you want to take care of logging
  yourself.
* The commit has the same short summary as the commit it fixes.
  This issue still persists. Open for suggestions.

Please state if v3 contains a log message that has been removed and is
still mandatory and I can add it if it makes sense.

> > +		rc = tpm_transmit_cmd(chip, NULL, buf.data,
> > PAGE_SIZE, 0, 0,
> > +				      "attempting the self test\n");
> 
> There shouldn't be a \n in the string: the failure message already
> appends one.

Oops, my bad, will fix it.

/Jarkko