From: Xiaoke Wang <xkernel.wang@foxmail.com>

kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it to
prevent potential wrong memory access.

Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
---
 drivers/iommu/msm_iommu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index 3a38352..697ad63 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -597,6 +597,10 @@ static void insert_iommu_master(struct device *dev,
 
 	if (list_empty(&(*iommu)->ctx_list)) {
 		master = kzalloc(sizeof(*master), GFP_ATOMIC);
+		if (!master) {
+			dev_err(dev, "Failed to allocate iommu_master\n");
+			return;
+		}
 		master->of_node = dev->of_node;
 		list_add(&master->list, &(*iommu)->ctx_list);
 		dev_iommu_priv_set(dev, master);
--