Hi,

On Mon, Apr 11, 2022 at 10:01:25AM +0300, Dan Carpenter wrote:

Hello Takashi Sakamoto,

The patch baa914cd81f5: "firewire: add kernel API to access CYCLE_TIME register" from Apr 5, 2022, leads to the following Smatch static checker warning:

drivers/firewire/core-cdev.c:1235 ioctl_get_cycle_timer2() error: uninitialized symbol 'cycle_time'.

drivers/firewire/core-cdev.c 1209 static int ioctl_get_cycle_timer2(struct client *client, union ioctl_arg *arg) 1210 { 1211 struct fw_cdev_get_cycle_timer2 *a = &arg->get_cycle_timer2; 1212 struct fw_card *card = client->device->card; 1213 struct timespec64 ts = {0, 0}; 1214 u32 cycle_time; 1215 int ret = 0; 1216 1217 local_irq_disable(); 1218 1219 ret = fw_card_read_cycle_time(card, &cycle_time); 1220 if (ret < 0) 1221 goto end; ^^^^^^^^ "cycle_time" not initialized on error path.

1222 
1223         switch (a->clk_id) {
1224         case CLOCK_REALTIME:      ktime_get_real_ts64(&ts);        break;
1225         case CLOCK_MONOTONIC:     ktime_get_ts64(&ts);                break;
1226         case CLOCK_MONOTONIC_RAW: ktime_get_raw_ts64(&ts);        break;
1227         default:
1228                 ret = -EINVAL;
1229         }
1230 end:
1231         local_irq_enable();
1232 
1233         a->tv_sec      = ts.tv_sec;
1234         a->tv_nsec     = ts.tv_nsec;

--> 1235 a->cycle_timer = cycle_time; 1236 1237 return ret; 1238 }

Thanks for the report. Indeed, it leaks the unidentified value on kernel stack to userspace. I'll post fix later.

Regards

Takashi Sakamoto