Re: [PATCH] tpm: ibmvtpm: Avoid error message when process gets signal while waiting

From: Stefan Berger <stefanb@linux.ibm.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Stefan Berger <stefanb@linux.vnet.ibm.com>,
	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>
Subject: Re: [PATCH] tpm: ibmvtpm: Avoid error message when process gets signal while waiting
Date: Thu, 29 Jul 2021 09:39:18 -0400	[thread overview]
Message-ID: <2add3eac-916e-5072-f62d-23c65e23fb17@linux.ibm.com> (raw)
In-Reply-To: <20210728215033.dhnekvksekalhcrn@kernel.org>


On 7/28/21 5:50 PM, Jarkko Sakkinen wrote:
> On Mon, Jul 26, 2021 at 11:00:51PM -0400, Stefan Berger wrote:
>> 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.
> We do not want to make a process uninterruptible. That would prevent
> killing it.

I guess we'll have to go back to this one then: 
https://www.spinics.net/lists/linux-integrity/msg16741.html

    Stefan


>
> /Jarkko