spi: lpspi: Avoid potential use-after-free in probe()

In the Linux kernel, the following vulnerability has been resolved:

spi: lpspi: Avoid potential use-after-free in probe()

fsl_lpspi_probe() is allocating/disposing memory manually with

spi_alloc_host()/spi_alloc_target(), but uses

devm_spi_register_controller(). In case of error after the latter call the

memory will be explicitly freed in the probe function by

spi_controller_put() call, but used afterwards by "devm" management outside

probe() (spi_unregister_controller() <- devm_spi_unregister() below).

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000070

...

Call trace:

kernfs_find_ns

kernfs_find_and_get_ns

sysfs_remove_group

sysfs_remove_groups

device_remove_attrs

device_del

spi_unregister_controller

devm_spi_unregister

release_nodes

devres_release_all

really_probe

driver_probe_device

__device_attach_driver

bus_for_each_drv

__device_attach

device_initial_probe

bus_probe_device

deferred_probe_work_func

process_one_work

worker_thread

kthread

ret_from_fork