From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> [ Upstream commit 16a8e2fbb2d49111004efc1c7342e083eafabeb0 ] 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@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211013133710.2679703-2-u.kleine-koenig@xxxxxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/spi/spi-mux.c | 7 +++++++ drivers/spi/spi.c | 12 ++++++------ 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/spi/spi-mux.c b/drivers/spi/spi-mux.c index 9708b7827ff7..f5d32ec4634e 100644 --- a/drivers/spi/spi-mux.c +++ b/drivers/spi/spi-mux.c @@ -137,6 +137,13 @@ static int spi_mux_probe(struct spi_device *spi) priv = spi_controller_get_devdata(ctlr); priv->spi = spi; + /* + * Increase lockdep class as these lock are taken while the parent bus + * already holds their instance's lock. + */ + lockdep_set_subclass(&ctlr->io_mutex, 1); + lockdep_set_subclass(&ctlr->add_lock, 1); + priv->mux = devm_mux_control_get(&spi->dev, NULL); if (IS_ERR(priv->mux)) { ret = dev_err_probe(&spi->dev, PTR_ERR(priv->mux), diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2c342bded058..3093e0041158 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2549,6 +2549,12 @@ struct spi_controller *__spi_alloc_controller(struct device *dev, return NULL; device_initialize(&ctlr->dev); + INIT_LIST_HEAD(&ctlr->queue); + spin_lock_init(&ctlr->queue_lock); + spin_lock_init(&ctlr->bus_lock_spinlock); + mutex_init(&ctlr->bus_lock_mutex); + mutex_init(&ctlr->io_mutex); + mutex_init(&ctlr->add_lock); ctlr->bus_num = -1; ctlr->num_chipselect = 1; ctlr->slave = slave; @@ -2821,12 +2827,6 @@ int spi_register_controller(struct spi_controller *ctlr) return id; ctlr->bus_num = id; } - INIT_LIST_HEAD(&ctlr->queue); - spin_lock_init(&ctlr->queue_lock); - spin_lock_init(&ctlr->bus_lock_spinlock); - mutex_init(&ctlr->bus_lock_mutex); - mutex_init(&ctlr->io_mutex); - mutex_init(&ctlr->add_lock); ctlr->bus_lock_flag = 0; init_completion(&ctlr->xfer_completion); if (!ctlr->max_dma_len) -- 2.33.0
