Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 30 Sep 2019 08:57:12 -0400
From:   Sasha Levin <sashal@kernel.org>
To:     Pavel Machek <pavel@ucw.cz>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Vadim Sukhomlinov <sukhomlinov@google.com>,
        Douglas Anderson <dianders@chromium.org>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: Re: [PATCH 4.19 33/63] tpm: Fix TPM 1.2 Shutdown sequence to prevent
 future TPM operations
Message-ID: <20190930125712.GS8171@sasha-vm>
References: <20190929135031.382429403@linuxfoundation.org>
 <20190929135038.128262622@linuxfoundation.org>
 <20190930061346.GA22914@atrey.karlin.mff.cuni.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Disposition: inline
In-Reply-To: <20190930061346.GA22914@atrey.karlin.mff.cuni.cz>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Sep 30, 2019 at 08:13:46AM +0200, Pavel Machek 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.
>
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index 46caadca916a0..dccc61af9ffab 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -187,12 +187,15 @@ static int tpm_class_shutdown(struct device *dev)
>>  {
>>  	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
>>
>> +	down_write(&chip->ops_sem);
>>  	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
>>  		down_write(&chip->ops_sem);
>>  		tpm2_shutdown(chip, TPM2_SU_CLEAR);
>>  		chip->ops = NULL;
>>  		up_write(&chip->ops_sem);
>>  	}
>> +	chip->ops = NULL;
>> +	up_write(&chip->ops_sem);
>
>This is wrong, it takes &chip->ops_sem twice, that can't be
>good. db4d8cb9c9f2af71c4d087817160d866ed572cc9 does not have that
>problem.

I agree. I've dropped it from 4.19 and 4.14.

Jarkko, can you take a look at this again please?

--
Thanks,
Sasha