From: "Hon Ching \\(Vicky\\) Lo" <honclo@xxxxxxxxxxxxxxxxxx>
The current code passes the address of tpm_chip as the argument to
dev_get_drvdata() without prior NULL check in
tpm_ibmvtpm_get_desired_dma. This resulted an oops during kernel
boot when vTPM is enabled in Power partition configured in active
memory sharing mode.
The vio_driver's get_desired_dma() is called before the probe(), which
for vtpm is tpm_ibmvtpm_probe, and it's this latter function that
initializes the driver and set data. Attempting to get data before
the probe() caused the problem.
This patch adds a NULL check to the tpm_ibmvtpm_get_desired_dma.
fixes: 9e0d39d8a6a0 ("tpm: Remove useless priv field in struct tpm_vendor_specific")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Hon Ching(Vicky) Lo <honclo@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkine <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
Backport for v4.9. I asked to Vicky to test my backport so this should be OK.
drivers/char/tpm/tpm_ibmvtpm.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c
index 946025a7413b..84eca4f93b82 100644
--- a/drivers/char/tpm/tpm_ibmvtpm.c
+++ b/drivers/char/tpm/tpm_ibmvtpm.c
@@ -295,6 +295,8 @@ static int tpm_ibmvtpm_remove(struct vio_dev *vdev)
}
kfree(ibmvtpm);
+ /* For tpm_ibmvtpm_get_desired_dma */
+ dev_set_drvdata(&vdev->dev, NULL);
return 0;
}
@@ -309,13 +311,16 @@ static int tpm_ibmvtpm_remove(struct vio_dev *vdev)
static unsigned long tpm_ibmvtpm_get_desired_dma(struct vio_dev *vdev)
{
struct tpm_chip *chip = dev_get_drvdata(&vdev->dev);
- struct ibmvtpm_dev *ibmvtpm = dev_get_drvdata(&chip->dev);
+ struct ibmvtpm_dev *ibmvtpm;
- /* ibmvtpm initializes at probe time, so the data we are
- * asking for may not be set yet. Estimate that 4K required
- * for TCE-mapped buffer in addition to CRQ.
- */
- if (!ibmvtpm)
+ /*
+ * ibmvtpm initializes at probe time, so the data we are
+ * asking for may not be set yet. Estimate that 4K required
+ * for TCE-mapped buffer in addition to CRQ.
+ */
+ if (chip)
+ ibmvtpm = dev_get_drvdata(&chip->dev);
+ else
return CRQ_RES_BUF_SIZE + PAGE_SIZE;
return CRQ_RES_BUF_SIZE + ibmvtpm->rtce_size;
--
2.11.0