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Subject: Re: [PATCH] tpm: ibmvtpm: Avoid -EINTR error when IMA talks to TPM
To:     Jarkko Sakkinen <jarkko@kernel.org>
Cc:     linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        peterhuewe@gmx.de, Nayna Jain <nayna@linux.ibm.com>,
        George Wilson <gcwilson@linux.ibm.com>
References: <20210209221339.875739-1-stefanb@linux.ibm.com>
 <YCZE8nf9ylXJTo4k@kernel.org>
From:   Stefan Berger <stefanb@linux.ibm.com>
Message-ID: <e850c8e8-76ab-548c-1f45-6e68d9faecac@linux.ibm.com>
Date:   Fri, 12 Feb 2021 17:32:14 -0500
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On 2/12/21 4:05 AM, Jarkko Sakkinen wrote:
> On Tue, Feb 09, 2021 at 05:13:39PM -0500, Stefan Berger wrote:
>> When IMA is taking measurements during compilation for example and a
>> user presses ctrl-c to abort the compilation, lots of these types of
>> messages will appear in the kernel log:
>>
>> [ 7406.275163] tpm tpm0: tpm_transmit: tpm_recv: error -4
>> [ 7406.275242] ima: Error Communicating to TPM chip, result: -4
>>
>> The issue is caused by the fact that the IBM vTPM driver's recv()
>> function is called immediately after send() without waiting for
>> status on whether a response was received. It currently waits for
>> the current command to finish using this call that ends up throwing
>> these error messages because it is 'interruptible':
> Why it is an issue?


The issue is the many kernel log entries we get when someone interrupts 
an application with ctrl-c while IMA is taking measurements of files it 
reads.I thought that was clear from the first paragraph.