In the 'wd_timer',the callback function executed by 'wd_expiration' could call wd_start,and g_wdtickbase might be updated.Subsequently, g_wdtickbase is incremented by the value of ticks, causing g_wdtickbase to be greater than the actual passage of time. Signed-off-by: yangguangcai <yangguangcai@xiaomi.com>