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    SubjectRe: [PATCH] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations
    On Fri, Jul 12, 2019 at 08:00:12AM -0700, Doug Anderson wrote:
    > Hi,
    >
    > On Fri, Jul 12, 2019 at 4:50 AM Greg KH <gregkh@linuxfoundation.org> wrote:
    > >
    > > On Thu, Jul 11, 2019 at 10:28:01AM -0700, Doug Anderson wrote:
    > > > Hi,
    > > >
    > > > On Thu, Jul 11, 2019 at 10:26 AM Greg KH <gregkh@linuxfoundation.org> wrote:
    > > > >
    > > > > On Thu, Jul 11, 2019 at 02:17:26PM -0300, Jason Gunthorpe wrote:
    > > > > > On Thu, Jul 11, 2019 at 07:04:37PM +0200, Greg KH wrote:
    > > > > > > On Thu, Jul 11, 2019 at 01:39:15PM -0300, Jason Gunthorpe wrote:
    > > > > > > > On Thu, Jul 11, 2019 at 09:29:19AM -0700, Douglas Anderson wrote:
    > > > > > > > > From: Vadim Sukhomlinov <sukhomlinov@google.com>
    > > > > > > > >
    > > > > > > > > commit db4d8cb9c9f2af71c4d087817160d866ed572cc9 upstream.
    > > > > > > > >
    > > > > > > > > TPM 2.0 Shutdown involve sending TPM2_Shutdown to TPM chip and disabling
    > > > > > > > > future TPM operations. TPM 1.2 behavior was different, future TPM
    > > > > > > > > operations weren't disabled, causing rare issues. This patch ensures
    > > > > > > > > that future TPM operations are disabled.
    > > > > > > > >
    > > > > > > > > Fixes: d1bd4a792d39 ("tpm: Issue a TPM2_Shutdown for TPM2 devices.")
    > > > > > > > > Cc: stable@vger.kernel.org
    > > > > > > > > Signed-off-by: Vadim Sukhomlinov <sukhomlinov@google.com>
    > > > > > > > > [dianders: resolved merge conflicts with mainline]
    > > > > > > > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
    > > > > > > > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    > > > > > > > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    > > > > > > > > This is the backport of the patch referenced above to 4.19 as was done
    > > > > > > > > in Chrome OS. See <https://crrev.com/c/1495114> for details. It
    > > > > > > > > presumably applies to some older kernels. NOTE that the problem
    > > > > > > > > itself has existed for a long time, but continuing to backport this
    > > > > > > > > exact solution to super old kernels is out of scope for me. For those
    > > > > > > > > truly interested feel free to reference the past discussion [1].
    > > > > > > > >
    > > > > > > > > Reason for backport: mainline has commit a3fbfae82b4c ("tpm: take TPM
    > > > > > > > > chip power gating out of tpm_transmit()") and commit 719b7d81f204
    > > > > > > > > ("tpm: introduce tpm_chip_start() and tpm_chip_stop()") and it didn't
    > > > > > > > > seem like a good idea to backport 17 patches to avoid the conflict.
    > > > > > > >
    > > > > > > > Careful with this, you can't backport this to any kernels that don't
    > > > > > > > have the sysfs ops locking changes or they will crash in sysfs code.
    > > > > > >
    > > > > > > And what commit added that?
    > > > > >
    > > > > > commit 2677ca98ae377517930c183248221f69f771c921
    > > > > > Author: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    > > > > > Date: Sun Nov 4 11:38:27 2018 +0200
    > > > > >
    > > > > > tpm: use tpm_try_get_ops() in tpm-sysfs.c.
    > > > > >
    > > > > > Use tpm_try_get_ops() in tpm-sysfs.c so that we can consider moving
    > > > > > other decorations (locking, localities, power management for example)
    > > > > > inside it. This direction can be of course taken only after other call
    > > > > > sites for tpm_transmit() have been treated in the same way.
    > > > > >
    > > > > > The last sentence suggests there are other patches needed too though..
    > > > >
    > > > > So 5.1. So does this original patch need to go into the 5.2 and 5.1
    > > > > kernels?
    > > >
    > > > The patch ("Fix TPM 1.2 Shutdown sequence to prevent future TPM
    > > > operations")? It's already done. It just got merge conflicts when
    > > > going back to 4.19 which is why I sent the backport.
    > >
    > > But the sysfs comment means I should not apply this backport then?
    > >
    > > Totally confused by this long thread, sorry.
    > >
    > > What am I supposed to do for the stable trees here?
    >
    > I think the answer is to drop my backport for now and Jarkko says
    > he'll take a fresh look at it in 2 weeks when he's back from his
    > leave. Thus my understanding:
    >
    > * On mainline: fixed
    >
    > * On 5.2 / 5.1: you've already got this picked to stable. Good
    >
    > * On 4.14 / 4.19: Jarkko will look at in 2 weeks.
    >
    > * On 4.9 and older: I'd propose skipping unless someone is known to
    > need a solution here.

    Thanks, that makes sense now.

    greg k-h

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