spi/mpc512x-psc: Avoid access to freed memory in device remove function

The call to spi_unregister_master() in the device remove function frees device
memory, and with it any device local data. However, device local data is still
accessed after the call to spi_unregister_master().

Acquire a reference to the SPI master device and release it after cleanup is
complete to solve the problem.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c
index 4c63f772780a..0a1e39e94d06 100644
--- a/drivers/spi/spi-mpc512x-psc.c
+++ b/drivers/spi/spi-mpc512x-psc.c
@@ -494,7 +494,7 @@ free_master:
 
 static int __devexit mpc512x_psc_spi_do_remove(struct device *dev)
 {
-        struct spi_master *master = dev_get_drvdata(dev);
+        struct spi_master *master = spi_master_get(dev_get_drvdata(dev));
         struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
 
         flush_workqueue(mps->workqueue);
@@ -503,6 +503,7 @@ static int __devexit mpc512x_psc_spi_do_remove(struct device *dev)
         free_irq(mps->irq, mps);
         if (mps->psc)
                 iounmap(mps->psc);
+        spi_master_put(master);
 
         return 0;
 }