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Subject[PATCH] tpm: ibmvtpm: Avoid error message when process gets signal while waiting
Date
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.

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 <nayna@linux.ibm.com>
Cc: George Wilson <gcwilson@linux.ibm.com>
Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
drivers/char/tpm/tpm_ibmvtpm.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 903604769de9..99b0442a5fdf 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -106,16 +106,13 @@ 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;
+ wait_event(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);

len = ibmvtpm->res_len;

@@ -206,7 +203,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
{
struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
bool retry = true;
- int rc, sig;
+ int rc;

if (!ibmvtpm->rtce_buf) {
dev_err(ibmvtpm->dev, "ibmvtpm device is not ready\n");
@@ -224,9 +221,7 @@ static int tpm_ibmvtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
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);
- if (sig)
- return -EINTR;
+ wait_event(ibmvtpm->wq, !ibmvtpm->tpm_processing_cmd);
}

spin_lock(&ibmvtpm->rtce_lock);
@@ -551,7 +546,7 @@ static void ibmvtpm_crq_process(struct ibmvtpm_crq *crq,
/* len of the data in rtce buffer */
ibmvtpm->res_len = be16_to_cpu(crq->len);
ibmvtpm->tpm_processing_cmd = false;
- wake_up_interruptible(&ibmvtpm->wq);
+ wake_up(&ibmvtpm->wq);
return;
default:
return;
--
2.31.1
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