Re: [PATCH 1/2] efi+tpm: Don't access event->count when it isn't mapped.
From: Jarkko Sakkinen
Date: Tue Aug 27 2019 - 07:03:51 EST
On Mon, Aug 26, 2019 at 10:44:31AM -0700, Matthew Garrett wrote:
> On Mon, Aug 26, 2019 at 9:28 AM Jarkko Sakkinen
> <jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
> > 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@xxxxxxxxxx>
> > > Tested-by: Lyude Paul <lyude@xxxxxxxxxx>
> > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> Acked-by: Matthew Garrett <mjg59@xxxxxxxxxx>
> Jarkko, these two should probably go to 5.3 if possible - I
> independently had a report of a system hitting this issue last week
> (Intel apparently put a surprising amount of data in the event logs on
> the NUCs).
OK, I can try to push them. I'll do PR today.