qcacmn: Add null pointer validation and fix initialization in dfs

Add validation check for memory allocation and initialize variable
before using.

Change-Id: If5215f4f034ea57884b252f8467c4e2ca227c952
CRs-Fixed: 2160749

umac/dfs/core/src/misc/dfs.c

@@ -293,10 +293,8 @@ bad1:
 		qdf_mem_free(dfs->pulses);
 		dfs->pulses = NULL;
 	}
-	if (dfs->events) {
-		qdf_mem_free(dfs->events);
-		dfs->events = NULL;
-	}
+	qdf_mem_free(dfs->events);
+	dfs->events = NULL;
 
 	return 1;
 }

umac/dfs/core/src/misc/dfs_zero_cac.c

@@ -534,6 +534,11 @@ void dfs_init_precac_list(struct wlan_dfs *dfs)
 
 				precac_entry = qdf_mem_malloc(
 					sizeof(*precac_entry));
+				if (!precac_entry) {
+					dfs_err(dfs, WLAN_DEBUG_DFS_ALWAYS,
+						"entry alloc fail for : %d", i);
+					continue;
+				}
 				precac_entry->vht80_freq =
 					ichan->dfs_ch_vhtop_ch_freq_seg1;
 				precac_entry->dfs = dfs;

umac/dfs/dispatcher/src/wlan_dfs_init_deinit_api.c

@@ -209,7 +209,7 @@ QDF_STATUS wlan_dfs_pdev_obj_create_notification(struct wlan_objmgr_pdev *pdev,
 QDF_STATUS wlan_dfs_pdev_obj_destroy_notification(struct wlan_objmgr_pdev *pdev,
 		void *arg)
 {
-	struct wlan_dfs *dfs;
+	struct wlan_dfs *dfs = NULL;
 
 	if (!pdev) {
 		dfs_err(dfs, WLAN_DEBUG_DFS_ALWAYS,  "PDEV is NULL");
@@ -219,7 +219,7 @@ QDF_STATUS wlan_dfs_pdev_obj_destroy_notification(struct wlan_objmgr_pdev *pdev,
 	dfs = wlan_pdev_get_dfs_obj(pdev);
 
 	/* DFS is NULL during unload. should we call this function before */
-	if (dfs != NULL) {
+	if (dfs) {
 		global_dfs_to_mlme.pdev_component_obj_detach(pdev,
 				WLAN_UMAC_COMP_DFS,
 				(void *)dfs);
@@ -237,7 +237,7 @@ static void dfs_scan_serialization_comp_info_cb(
 		struct wlan_objmgr_vdev *vdev,
 		union wlan_serialization_rules_info *comp_info)
 {
-	struct wlan_dfs *dfs;
+	struct wlan_dfs *dfs = NULL;
 	struct wlan_objmgr_pdev *pdev;
 
 	if (!comp_info) {