spi/omap2_mcspi: Check params before dereference or use

Check spi->chip_select for range before use.

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

1 files changed, 11 insertions, 8 deletions

diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 6df85537bd19..b3a94ca0a75a 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -834,7 +834,6 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
         struct omap2_mcspi_cs   *cs;
 
         mcspi = spi_master_get_devdata(spi->master);
-        mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 
         if (spi->controller_state) {
                 /* Unlink controller state from context save list */
@@ -844,13 +843,17 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
                 kfree(spi->controller_state);
         }
 
-        if (mcspi_dma->dma_rx_channel != -1) {
-                omap_free_dma(mcspi_dma->dma_rx_channel);
-                mcspi_dma->dma_rx_channel = -1;
-        }
-        if (mcspi_dma->dma_tx_channel != -1) {
-                omap_free_dma(mcspi_dma->dma_tx_channel);
-                mcspi_dma->dma_tx_channel = -1;
+        if (spi->chip_select < spi->master->num_chipselect) {
+                mcspi_dma = &mcspi->dma_channels[spi->chip_select];
+
+                if (mcspi_dma->dma_rx_channel != -1) {
+                        omap_free_dma(mcspi_dma->dma_rx_channel);
+                        mcspi_dma->dma_rx_channel = -1;
+                }
+                if (mcspi_dma->dma_tx_channel != -1) {
+                        omap_free_dma(mcspi_dma->dma_tx_channel);
+                        mcspi_dma->dma_tx_channel = -1;
+                }
         }
 }