eabad7ba2c
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL: At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable). Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL. Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Fixes: 39d0099f9439 ("powerpc/pseries: Add shutdown() to vio_driver and vio_bus") Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Tested-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.