dell-wmi, hp-wmi, msi-wmi: check wmi_get_event_data() return value

When acpi_evaluate_object() is passed ACPI_ALLOCATE_BUFFER,
the caller must kfree the returned buffer if AE_OK is returned.

The callers of wmi_get_event_data() pass ACPI_ALLOCATE_BUFFER,
and thus must check its return value before accessing
or kfree() on the buffer.
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/platform/x86/dell-wmi.c

@@ -202,8 +202,13 @@ static void dell_wmi_notify(u32 value, void *context)
 	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
 	static struct key_entry *key;
 	union acpi_object *obj;
+	acpi_status status;
 
-	wmi_get_event_data(value, &response);
+	status = wmi_get_event_data(value, &response);
+	if (status != AE_OK) {
+		printk(KERN_INFO "dell-wmi: bad event status 0x%x\n", status);
+		return;
+	}
 
 	obj = (union acpi_object *)response.pointer;
 

drivers/platform/x86/hp-wmi.c

@@ -338,8 +338,13 @@ static void hp_wmi_notify(u32 value, void *context)
 	static struct key_entry *key;
 	union acpi_object *obj;
 	int eventcode;
+	acpi_status status;
 
-	wmi_get_event_data(value, &response);
+	status = wmi_get_event_data(value, &response);
+	if (status != AE_OK) {
+		printk(KERN_INFO "hp-wmi: bad event status 0x%x\n", status);
+		return;
+	}
 
 	obj = (union acpi_object *)response.pointer;
 

drivers/platform/x86/msi-wmi.c

@@ -149,8 +149,13 @@ static void msi_wmi_notify(u32 value, void *context)
 	static struct key_entry *key;
 	union acpi_object *obj;
 	ktime_t cur;
+	acpi_status status;
 
-	wmi_get_event_data(value, &response);
+	status = wmi_get_event_data(value, &response);
+	if (status != AE_OK) {
+		printk(KERN_INFO DRV_PFX "bad event status 0x%x\n", status);
+		return;
+	}
 
 	obj = (union acpi_object *)response.pointer;