cputime_t ptime = cputime_add(utime, stime);
 
        list_for_each_entry_safe(timer, next, head, entry) {
+               put_task_struct(timer->task);
                timer->task = NULL;
                list_del_init(&timer->entry);
                if (cputime_lt(timer->expires.cpu, ptime)) {
 
        ++head;
        list_for_each_entry_safe(timer, next, head, entry) {
+               put_task_struct(timer->task);
                timer->task = NULL;
                list_del_init(&timer->entry);
                if (cputime_lt(timer->expires.cpu, utime)) {
 
        ++head;
        list_for_each_entry_safe(timer, next, head, entry) {
+               put_task_struct(timer->task);
                timer->task = NULL;
                list_del_init(&timer->entry);
                if (timer->expires.sched < sched_time) {