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Subject: Re: [PATCH] tpm: ibmvtpm: Avoid error message when process gets
 signal while waiting
To:     Jarkko Sakkinen <jarkko@kernel.org>,
        Stefan Berger <stefanb@linux.vnet.ibm.com>
Cc:     peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, Nayna Jain <nayna@linux.ibm.com>,
        George Wilson <gcwilson@linux.ibm.com>,
        Nageswara R Sastry <rnsastry@linux.ibm.com>
References: <20210712162505.205943-1-stefanb@linux.vnet.ibm.com>
 <20210727024225.swqy5ypcytsngpd6@kernel.org>
From:   Stefan Berger <stefanb@linux.ibm.com>
Message-ID: <ad4011fb-fc1f-4019-9856-7d171db3255c@linux.ibm.com>
Date:   Mon, 26 Jul 2021 23:00:51 -0400
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On 7/26/21 10:42 PM, Jarkko Sakkinen wrote:
> On Mon, Jul 12, 2021 at 12:25:05PM -0400, Stefan Berger wrote:
>> From: Stefan Berger <stefanb@linux.ibm.com>
>>
>> When rngd is run as root then lots of these types of message will appear
>> in the kernel log if the TPM has been configure to provide random bytes:
>>
>> [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4
>>
>> The issue is caused by the following call that is interrupted while
>> waiting for the TPM's response.
>>
>> sig = wait_event_interruptible(ibmvtpm->wq,
>>                                 !ibmvtpm->tpm_processing_cmd);
>>
>> The solution is to use wait_event() instead.
> Why?

So it becomes uninterruptible and these error messages go away.

     Stefan

>
> /Jarkko