linux-kernel - Re: [PATCH 1/2] efi+tpm: Don't access event->count when it isn't mapped.

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Message-ID: <20190826162823.4mxkwhd7mbtro3zy@linux.intel.com>
Date:   Mon, 26 Aug 2019 19:28:23 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Peter Jones <pjones@...hat.com>
Cc:     Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Roberto Sassu <roberto.sassu@...wei.com>,
        Matthew Garrett <mjg59@...gle.com>,
        Bartosz Szczepanek <bsz@...ihalf.com>,
        Lyude Paul <lyude@...hat.com>, linux-efi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] efi+tpm: Don't access event->count when it isn't
 mapped.

On Mon, Aug 26, 2019 at 11:30:27AM -0400, Peter Jones wrote:
> Some machines generate a lot of event log entries.  When we're
> iterating over them, the code removes the old mapping and adds a
> new one, so once we cross the page boundary we're unmapping the page
> with the count on it.  Hilarity ensues.
> 
> This patch keeps the info from the header in local variables so we don't
> need to access that page again or keep track of if it's mapped.
> 
> Signed-off-by: Peter Jones <pjones@...hat.com>
> Tested-by: Lyude Paul <lyude@...hat.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

/Jarkko