[PATCH v2 1/5] spi: imx: fix use-after-free on unbind

[Johan Hovold <johan@kernel.org>]

The SPI subsystem frees the controller and any subsystem allocated
driver data as part of deregistration (unless the allocation is device
managed).

Take another reference before deregistering the controller so that the
driver data is not freed until the driver is done with it.

Fixes: 307c897db762 ("spi: spi-imx: replace struct spi_imx_data::bitbang by pointer to struct spi_controller")
Cc: stable@vger.kernel.org	# 5.19
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/spi/spi-imx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 64c6c09e1e7b..a8d90c86a8a1 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -2401,6 +2401,8 @@ static void spi_imx_remove(struct platform_device *pdev)
 	struct spi_imx_data *spi_imx = spi_controller_get_devdata(controller);
 	int ret;
 
+	spi_controller_get(controller);
+
 	spi_unregister_controller(controller);
 
 	ret = pm_runtime_get_sync(spi_imx->dev);
@@ -2414,6 +2416,8 @@ static void spi_imx_remove(struct platform_device *pdev)
 	pm_runtime_disable(spi_imx->dev);
 
 	spi_imx_sdma_exit(spi_imx);
+
+	spi_controller_put(controller);
 }
 
 static int spi_imx_runtime_resume(struct device *dev)
-- 
2.52.0