Move "exit_robust_list" into mm_release()

We don't want to get rid of the futexes just at exit() time, we want to
drop them when doing an execve() too, since that gets rid of the
previous VM image too.

Doing it at mm_release() time means that we automatically always do it
when we disassociate a VM map from the task.

Reported-by: pageexec@freemail.hu
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Alex Efros <powerman@powerman.name>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
asmlinkage long sys_waitid(int which, pid_t upid,
			   struct siginfo __user *infop, int options,
			   struct rusage __user *ru)
{
	struct pid *pid = NULL;
	enum pid_type type;
	long ret;

	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
		return -EINVAL;
	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
		return -EINVAL;

	switch (which) {
	case P_ALL:
		type = PIDTYPE_MAX;
		break;
	case P_PID:
		type = PIDTYPE_PID;
		if (upid <= 0)
			return -EINVAL;
		break;
	case P_PGID:
		type = PIDTYPE_PGID;
		if (upid <= 0)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	if (type < PIDTYPE_MAX)
		pid = find_get_pid(upid);
	ret = do_wait(type, pid, options, infop, NULL, ru);
	put_pid(pid);

	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(5, ret, which, upid, infop, options, ru);
	return ret;
}

asmlinkage long sys_waitid(int which, pid_t upid,
			   struct siginfo __user *infop, int options,
			   struct rusage __user *ru)
{
	struct pid *pid = NULL;
	enum pid_type type;
	long ret;

	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
		return -EINVAL;
	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
		return -EINVAL;

	switch (which) {
	case P_ALL:
		type = PIDTYPE_MAX;
		break;
	case P_PID:
		type = PIDTYPE_PID;
		if (upid <= 0)
			return -EINVAL;
		break;
	case P_PGID:
		type = PIDTYPE_PGID;
		if (upid <= 0)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	if (type < PIDTYPE_MAX)
		pid = find_get_pid(upid);
	ret = do_wait(type, pid, options, infop, NULL, ru);
	put_pid(pid);

	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(5, ret, which, upid, infop, options, ru);
	return ret;
}
