vTPM: Fix missing NULL check
authorHon Ching \(Vicky\) Lo <honclo@linux.vnet.ibm.com>
Wed, 15 Mar 2017 05:28:07 +0000 (01:28 -0400)
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Mon, 3 Apr 2017 19:46:02 +0000 (22:46 +0300)
commit31574d321c70f6d3b40fe98f9b2eafd9a903fef9
tree9b87dc75357ad6ad4d4fc4bee8361b968e6b4c5f
parent8569defde8057258835c51ce01a33de82e14b148
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: <stable@vger.kernel.org>
Signed-off-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkine <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
drivers/char/tpm/tpm_ibmvtpm.c