From: Michael Walle michael@walle.cc
commit 6c53b45c71b4920b5e62f0ea8079a1da382b9434 upstream.
Commit 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") introduced a per-controller mutex. But mutex_unlock() of said lock is called after the controller is already freed:
spi_unregister_controller(ctlr) -> put_device(&ctlr->dev) -> spi_controller_release(dev) -> mutex_unlock(&ctrl->add_lock)
Move the put_device() after the mutex_unlock().
Fixes: 6098475d4cb4 ("spi: Fix deadlock when adding SPI controllers on SPI buses") Signed-off-by: Michael Walle michael@walle.cc Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Reviewed-by: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org # v5.15 Link: https://lore.kernel.org/r/20211111083713.3335171-1-michael@walle.cc Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/spi/spi.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -3020,12 +3020,6 @@ void spi_unregister_controller(struct sp
device_del(&ctlr->dev);
- /* Release the last reference on the controller if its driver - * has not yet been converted to devm_spi_alloc_master/slave(). - */ - if (!ctlr->devm_allocated) - put_device(&ctlr->dev); - /* free bus id */ mutex_lock(&board_lock); if (found == ctlr) @@ -3034,6 +3028,12 @@ void spi_unregister_controller(struct sp
if (IS_ENABLED(CONFIG_SPI_DYNAMIC)) mutex_unlock(&ctlr->add_lock); + + /* Release the last reference on the controller if its driver + * has not yet been converted to devm_spi_alloc_master/slave(). + */ + if (!ctlr->devm_allocated) + put_device(&ctlr->dev); } EXPORT_SYMBOL_GPL(spi_unregister_controller);