From 31574d321c70f6d3b40fe98f9b2eafd9a903fef9 Mon Sep 17 00:00:00 2001 From: "Hon Ching \\(Vicky\\) Lo" Date: Wed, 15 Mar 2017 01:28:07 -0400 Subject: [PATCH] vTPM: Fix missing NULL check 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: Signed-off-by: Hon Ching(Vicky) Lo Reviewed-by: Jarkko Sakkine Signed-off-by: Jarkko Sakkinen --- drivers/char/tpm/tpm_ibmvtpm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm_ibmvtpm.c b/drivers/char/tpm/tpm_ibmvtpm.c index 1b9d61ffe991..f01d083eced2 100644 --- a/drivers/char/tpm/tpm_ibmvtpm.c +++ b/drivers/char/tpm/tpm_ibmvtpm.c @@ -299,6 +299,8 @@ 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; } @@ -313,14 +315,16 @@ 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) + if (chip) + ibmvtpm = dev_get_drvdata(&chip->dev); + else return CRQ_RES_BUF_SIZE + PAGE_SIZE; return CRQ_RES_BUF_SIZE + ibmvtpm->rtce_size; -- 2.20.1