spi/omap2_mcspi: fix NULL pointer dereference

Check spi->controller_state before dereferencing.

Shows up NULL here when using spi_alloc_device()/spi_add_device()
and spi_add_device() fails before spi_setup(). Calling spi_dev_put()
on the leftover spi_device results in the error.

Signed-off-by: Scott Ellis <scott@jumpnowtek.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 715c518b1b68..87d44eeaaa7b 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -751,11 +751,13 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
         mcspi = spi_master_get_devdata(spi->master);
         mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 
-        /* Unlink controller state from context save list */
-        cs = spi->controller_state;
-        list_del(&cs->node);
+        if (spi->controller_state) {
+                /* Unlink controller state from context save list */
+                cs = spi->controller_state;
+                list_del(&cs->node);
 
-        kfree(spi->controller_state);
+                kfree(spi->controller_state);
+        }
 
         if (mcspi_dma->dma_rx_channel != -1) {
                 omap_free_dma(mcspi_dma->dma_rx_channel);