[PATCH] posix-timers: fix task accounting

Make sure we release the task struct properly when releasing pending
timers.

release_task() does write_lock_irq(&tasklist_lock), so it can't race
with run_posix_cpu_timers() on any cpu.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/posix-cpu-timers.c

@@ -424,6 +424,7 @@ static void cleanup_timers(struct list_head *head,
 	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)) {
@@ -436,6 +437,7 @@ static void cleanup_timers(struct list_head *head,
 
 	++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)) {
@@ -448,6 +450,7 @@ static void cleanup_timers(struct list_head *head,
 
 	++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) {