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Fri, 30 Jul 2021 04:15:06 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 76802A4062; Fri, 30 Jul 2021 04:15:04 +0000 (GMT) Received: from Nageswaras-MacBook-Pro-2.local (unknown [9.43.87.139]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 30 Jul 2021 04:15:04 +0000 (GMT) Subject: Re: [PATCH] tpm: ibmvtpm: Avoid error message when process gets signal while waiting To: Stefan Berger , jarkko@kernel.org Cc: peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Berger , Nayna Jain , George Wilson References: <20210729161931.3609894-1-stefanb@linux.vnet.ibm.com> From: Nageswara Sastry Message-ID: <080eeff4-b75f-e1d5-160b-4a7aca54605f@linux.ibm.com> Date: Fri, 30 Jul 2021 09:45:02 +0530 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 In-Reply-To: <20210729161931.3609894-1-stefanb@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: uPadqPRZJDdCb-AyJKgwKd_jXIyEa_6a X-Proofpoint-GUID: KaobbLhQD8pRE7LAMw6fYfoqGOYQzQj_ Content-Transfer-Encoding: 7bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-30_03:2021-07-29,2021-07-30 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 suspectscore=0 adultscore=0 clxscore=1015 impostorscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2107300023 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/07/21 9:49 pm, Stefan Berger wrote: > From: Stefan Berger > > 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); > > Rather than waiting for the response in the low level driver, have it use > the polling loop in tpm_try_transmit() that uses a command's duration to > poll until a result has been returned by the TPM, thus ending when the > timeout has occurred but not responding to signals and ctrl-c anymore. > To stay in this polling loop we now extend tpm_ibmvtpm_status() to return > PM_STATUS_BUSY for as long as the vTPM is busy. Since we will need the > timeouts in this loop now we get the TPM 1.2 and TPM 2 timeouts with > tpm_get_timeouts(). > > Rename the tpm_processing_cmd to tpm_status in ibmvtpm_dev and set the > TPM_STATUS_BUSY flag while the vTPM is busy processing a command. > > To recreat the issue start rngd like this: > > sudo rngd -r /dev/hwrng -t > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1981473 > Fixes: 6674ff145eef ("tpm_ibmvtpm: properly handle interrupted packet receptions") > Cc: Nayna Jain > Cc: George Wilson > Reported-by: Nageswara R Sastry > Signed-off-by: Stefan Berger Tested-by: Nageswara R Sastry Tested with rngd -r /dev/hwrng -t rngd -r /dev/tpm0 -t There are no tpm errors seen. Thank you. > --- > drivers/char/tpm/tpm_ibmvtpm.c | 31 ++++++++++++++++++------------- > drivers/char/tpm/tpm_ibmvtpm.h | 3 ++- > 2 files changed, 20 insertions(+), 14 deletions(-) > > diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c > index 903604769de9..5d795866b483 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.c > +++ b/drivers/char/tpm/tpm_ibmvtpm.c > @@ -106,17 +106,12 @@ static int tpm_ibmvtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count) > { > struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); > u16 len; > - int sig; > > if (!ibmvtpm->rtce_buf) { > dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n"); > return 0; > } > > - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); > - if (sig) > - return -EINTR; > - > len = ibmvtpm->res_len; > > if (count < len) { > @@ -220,11 +215,12 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > return -EIO; > } > > - if (ibmvtpm->tpm_processing_cmd) { > + if ((ibmvtpm->tpm_status & TPM_STATUS_BUSY)) { > dev_info(ibmvtpm->dev, > "Need to wait for TPM to finish\n"); > /* wait for previous command to finish */ > - sig = wait_event_interruptible(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd); > + sig = wait_event_interruptible(ibmvtpm->wq, > + (ibmvtpm->tpm_status & TPM_STATUS_BUSY) == 0); > if (sig) > return -EINTR; > } > @@ -237,7 +233,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > * set the processing flag before the Hcall, since we may get the > * result (interrupt) before even being able to check rc. > */ > - ibmvtpm->tpm_processing_cmd = true; > + ibmvtpm->tpm_status |= TPM_STATUS_BUSY; > > again: > rc = ibmvtpm_send_crq(ibmvtpm->vdev, > @@ -255,7 +251,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count) > goto again; > } > dev_err(ibmvtpm->dev, "tpm_ibmvtpm_send failed rc=%d\n", rc); > - ibmvtpm->tpm_processing_cmd = false; > + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; > } > > spin_unlock(&ibmvtpm->rtce_lock); > @@ -269,7 +265,9 @@ static void tpm_ibmvtpm_cancel(struct tpm_chip *chip) > > static u8 tpm_ibmvtpm_status(struct tpm_chip *chip) > { > - return 0; > + struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev); > + > + return ibmvtpm->tpm_status; > } > > /** > @@ -457,7 +455,7 @@ static const struct tpm_class_ops tpm_ibmvtpm = { > .send = tpm_ibmvtpm_send, > .cancel = tpm_ibmvtpm_cancel, > .status = tpm_ibmvtpm_status, > - .req_complete_mask = 0, > + .req_complete_mask = TPM_STATUS_BUSY, > .req_complete_val = 0, > .req_canceled = tpm_ibmvtpm_req_canceled, > }; > @@ -550,7 +548,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq, > case VTPM_TPM_COMMAND_RES: > /* len of the data in rtce buffer */ > ibmvtpm->res_len = be16_to_cpu(crq->len); > - ibmvtpm->tpm_processing_cmd = false; > + ibmvtpm->tpm_status &= ~TPM_STATUS_BUSY; > wake_up_interruptible(&ibmvtpm->wq); > return; > default: > @@ -688,8 +686,15 @@ 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); > if (rc) > goto init_irq_cleanup; > diff --git a/drivers/char/tpm/tpm_ibmvtpm.h b/drivers/char/tpm/tpm_ibmvtpm.h > index b92aa7d3e93e..252f1cccdfc5 100644 > --- a/drivers/char/tpm/tpm_ibmvtpm.h > +++ b/drivers/char/tpm/tpm_ibmvtpm.h > @@ -41,7 +41,8 @@ struct ibmvtpm_dev { > wait_queue_head_t wq; > u16 res_len; > u32 vtpm_version; > - bool tpm_processing_cmd; > + u8 tpm_status; > +#define TPM_STATUS_BUSY (1 << 0) /* vtpm is processing a command */ > }; > > #define CRQ_RES_BUF_SIZE PAGE_SIZE > -- Thanks and Regards R.Nageswara Sastry