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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Stefan Berger <stefanb@linux.ibm.com>
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: Fri, 30 Jul 2021 03:57:44 +0300	[thread overview]
Message-ID: <20210730005744.ph7x6nme5ngtpf43@kernel.org> (raw)
In-Reply-To: <2add3eac-916e-5072-f62d-23c65e23fb17@linux.ibm.com>

On Thu, Jul 29, 2021 at 09:39:18AM -0400, Stefan Berger wrote:
> 
> 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

Makes a heck lot more sense.

There's a typo in the commit message: PM_STATUS_BUSY 

Also the commit message lacks explanation of this change completely:

@@ -690,8 +688,15 @@ static int tpm_ibmvtpm_probe(struct vio_dev *vio_dev,
 		goto init_irq_cleanup;
 	}
 
-	if (!strcmp(id->compat, "IBM,vtpm20")) {
+
+	if (!strcmp(id->compat, "IBM,vtpm20"))
 		chip->flags |= TPM_CHIP_FLAG_TPM2;
+
+	rc = tpm_get_timeouts(chip);
+	if (rc)
+		goto init_irq_cleanup;
+
+	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 		rc = tpm2_get_cc_attrs_tbl(chip);

The last paragraph should be rewritten in imperative form.

Finally, you could simplify the fix by simply changing the type of
tpm_processing_cmd to u8, and just set it to 'true' and 'false',
which will set the first bit.

/Jarkko

  reply	other threads:[~2021-07-30  0:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12 16:25 Stefan Berger
2021-07-13  5:03 ` Nageswara Sastry
2021-07-27  2:42 ` Jarkko Sakkinen
2021-07-27  3:00   ` Stefan Berger
2021-07-28 21:50     ` Jarkko Sakkinen
2021-07-29 13:39       ` Stefan Berger
2021-07-30  0:57         ` Jarkko Sakkinen [this message]
2021-07-30 11:45           ` Stefan Berger
2021-07-29 16:19 Stefan Berger
2021-07-30  4:15 ` Nageswara Sastry

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