diff --git a/drivers/video/fbdev/msm/mdss_smmu.c b/drivers/video/fbdev/msm/mdss_smmu.c
index 9906f10a7911..9a00eff9ade9 100644
--- a/drivers/video/fbdev/msm/mdss_smmu.c
+++ b/drivers/video/fbdev/msm/mdss_smmu.c
@@ -172,6 +172,7 @@ static int mdss_smmu_attach_v2(struct mdss_data_type *mdata)
 	struct mdss_smmu_client *mdss_smmu;
 	int i, rc = 0;
 
+	mutex_lock(&mdp_iommu_lock);
 	for (i = 0; i < MDSS_IOMMU_MAX_DOMAIN; i++) {
 		if (!mdss_smmu_is_valid_domain_type(mdata, i))
 			continue;
@@ -203,9 +204,12 @@ static int mdss_smmu_attach_v2(struct mdss_data_type *mdata)
 			}
 		} else {
 			pr_err("iommu device not attached for domain[%d]\n", i);
+			mutex_unlock(&mdp_iommu_lock);
 			return -ENODEV;
 		}
 	}
+	mutex_unlock(&mdp_iommu_lock);
+
 	return 0;
 
 err:
@@ -217,6 +221,8 @@ err:
 			mdss_smmu->domain_attached = false;
 		}
 	}
+	mutex_unlock(&mdp_iommu_lock);
+
 	return rc;
 }
 
@@ -231,6 +237,7 @@ static int mdss_smmu_detach_v2(struct mdss_data_type *mdata)
 	struct mdss_smmu_client *mdss_smmu;
 	int i;
 
+	mutex_lock(&mdp_iommu_lock);
 	for (i = 0; i < MDSS_IOMMU_MAX_DOMAIN; i++) {
 		if (!mdss_smmu_is_valid_domain_type(mdata, i))
 			continue;
@@ -239,6 +246,8 @@ static int mdss_smmu_detach_v2(struct mdss_data_type *mdata)
 		if (mdss_smmu && mdss_smmu->dev && !mdss_smmu->handoff_pending)
 			mdss_smmu_enable_power(mdss_smmu, false);
 	}
+	mutex_unlock(&mdp_iommu_lock);
+
 	return 0;
 }