16a8e2fbb2
io_mutex is taken by spi_setup() and spi-mux's .setup() callback calls spi_setup() which results in a nested lock of io_mutex. add_lock is taken by spi_add_device(). The device_add() call in there can result in calling spi-mux's .probe() callback which registers its own spi controller which in turn results in spi_add_device() being called again. To fix this initialize the controller's locks already in spi_alloc_controller() to give spi_mux_probe() a chance to set the lockdep subclass. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20211013133710.2679703-2-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@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.