DMA: OF: Check properties value before running be32_to_cpup() on it

In of_dma_controller_register() routine we are calling of_get_property() as an
parameter to be32_to_cpup(). In case the property doesn't exist we will get a
crash.

This patch changes this code to check if we got a valid property first and then
runs be32_to_cpup() on it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index 6036cd0..00db454 100644 (file)
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -93,6 +93,7 @@ int of_dma_controller_register(struct device_node *np,
 {
        struct of_dma   *ofdma;
        int             nbcells;
+       const __be32    *prop;
 
        if (!np || !of_dma_xlate) {
                pr_err("%s: not enough information provided\n", __func__);
@@ -103,8 +104,11 @@ int of_dma_controller_register(struct device_node *np,
        if (!ofdma)
                return -ENOMEM;
 
-       nbcells = be32_to_cpup(of_get_property(np, "#dma-cells", NULL));
-       if (!nbcells) {
+       prop = of_get_property(np, "#dma-cells", NULL);
+       if (prop)
+               nbcells = be32_to_cpup(prop);
+
+       if (!prop || !nbcells) {
                pr_err("%s: #dma-cells property is missing or invalid\n",
                       __func__);
                kfree(ofdma);