Re: [PATCH v2] tpm_tis: Add missing tpm_request/relinquish_locality calls

From: Jarkko Sakkinen <jarkko@kernel.org>
To: Dirk Gouders <dirk@gouders.net>
Cc: Lukasz Majczak <lma@semihalf.com>,
	Guenter Roeck <linux@roeck-us.net>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Tj <ml.linux@elloe.vision>, Peter Huewe <peterhuewe@gmx.de>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
	Radoslaw Biernacki <rad@semihalf.com>,
	Marcin Wojtas <mw@semihalf.com>, Alex Levin <levinale@google.com>
Subject: Re: [PATCH v2] tpm_tis: Add missing tpm_request/relinquish_locality calls
Date: Tue, 2 Feb 2021 18:29:19 +0200	[thread overview]
Message-ID: <YBl933XkQimq5elb@kernel.org> (raw)
In-Reply-To: <ghwnvtwifq.fsf@gouders.net>

On Sun, Jan 31, 2021 at 10:43:05AM +0100, Dirk Gouders wrote:
> Jarkko Sakkinen <jarkko@kernel.org> writes:
> 
> > On Thu, 2021-01-28 at 14:07 +0100, Lukasz Majczak wrote:
> >> There is a missing call to tpm_request_locality before the call to
> >> the tpm_get_timeouts() and tpm_tis_probe_irq_single(). As the current
> >> approach might work for tpm2, it fails for tpm1.x - in that case
> >> call to tpm_get_timeouts() or tpm_tis_probe_irq_single()
> >> without locality fails and in turn causes tpm_tis_core_init() to fail.
> >> Tested on Samsung Chromebook Pro (Caroline).
> >> 
> >> Signed-off-by: Lukasz Majczak <lma@semihalf.com>
> >
> > Is it possible that you test against linux-next and see if any
> > problems still arise? I've applied the locality fixes from James.
> 
> I tested current linux-next and the warning still appears,
> unfortunately.
> 
> I then incrementally applied further patches from James' series [1] and
> after "[PATCH v2 4/5] tpm_tis: fix IRQ probing" the warning has gone:
> 
> # dmesg | grep tpm
> [    7.220410] tpm_tis STM0125:00: 2.0 TPM (device-id 0x0, rev-id 78)
> [    7.322564] Modules linked in: iwlmvm(+) btusb btrtl btbcm btintel mac80211 amdgpu(+) iwlwifi drm_ttm_helper tpm_crb sdhci_pci ttm cqhci gpu_sched sdhci ccp cfg80211 rng_core tpm_tis tpm_tis_core tpm thinkpad_acpi(+) wmi nvram pinctrl_amd
> 
> You might notice there is another warning but that is rtc related and I
> still have to find out if that is something I should report.

1/5 and 2/5 are on the other hand unconditionally "right things" to
do. In your case the resulting state will anyway just result a polling
driver and the kernel state remains stable.

WARN_ONCE() is clearly an overkill, as kernel does not have inconsistent
state. Using WARN_ONCE() was a mistake.

I sent this fix: https://lore.kernel.org/linux-integrity/3936843b-c0da-dd8c-8aa9-90aa3b49d525@linux.ibm.com/T/#t

It will turn WARN_ONCE() to pr_warn_once() and also add the status code
to klog entry. It's sufficient in this case. For 3/5-5/5 we need more
time.

/Jarkko